Homework Help > CBSE Class 08
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who is alexnder the great?

Answers:

Aap Ke papa
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I spent 5% of my total income in charity, 22% in buisness and 53% in family. Now i Had Rs. 2163 and forty paisa. Find my total income

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Total expenditure = 5% + 22% + 53% = 80%
Money left = 100%  80% = 20%
Let total income be Rs. x.
According to question,
20% of x = 2163.40
20/100 × x = 2163.40
x = 2163.40 × 100 ÷ 20
x = Rs. 10817
Therefore total income is Rs. 10817.
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A person has deposited amount at 12% rate find out years to make principle double.

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Let amount deposited be P. Then amount after required years will be 2P.
Now, S.I. = P x R x T / 100
S.I. = P x 12 x T / 100 = 2PT/25
Amount = P + S.I
2P = P + (2PT/25)
P = 2PT/25
2T = 25
T = 12.5
Therefore the time required for principal double is 12.5 years.
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At what rate , Rs 9900 amount to 13365 in 5 years

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SI = (P X R X T )/100
P = Rs. 9900
A= Rs. 13,365
SI = AP = Rs.3465
T = 5years
3465 X 100 = 9900 X R X 5
R = 7%
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A cylindrical roller has perimeter 3.5 m and dimeter 2.8 m if roller rolled 200 times , find area of playground

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The cube of metal 3,4,5cm are melted and made in to single cube. Find the side of cube.

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Volume of single cube = 3^{3}+4^{3}+5^{3}
a^{3} = 27+64+125
a^{3}= 216
a^{3}= 6^{3}
a=6cm
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A person throw bucjet if water of square shape if total water is 8 litre . Find out side of bucket.

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Ans. Volume of water = 8 L = 0.008m^{3}
Let Side of bucket = x m
Volume of bucket = Volume of water
=> x^{3} = 0.008
=> x^{3} = (0.2)^{3}
=> x = 0.2 m = 20 cm
Side of bucket is 20 cm
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There are chikens with color 50 yellow 50 black and 50 red. Find inique probability of all colors.

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At what rate % per annum will rs 50000 to rs 86400 in 3 years if interest compounded annually

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Ans. Amount (A)= 86400
Time(n) = 3 years
Principal (P)= 50000
Let rate (r) = r%
Then We Know,
{tex}A = P \times ({1 +{r\over 100}})^n{/tex}
{tex}=> 86400 = 50000\times ({1+{r\over 100}})^3{/tex}
{tex}=> {86400\over 50000} = ({1+{r\over 100}})^3{/tex}
{tex}=> {216\over 125} = ({1+{r\over 100}})^3{/tex}
{tex}=> ({6\over 5})^3= ({1+{r\over 100}})^3{/tex}
On comparing, We get
{tex}=> ({6\over 5})= ({1+{r\over 100}}){/tex}
{tex}=> {6\over 5}  1= {r\over 100}{/tex}
{tex}=> {1\over 5} = {r\over 100} => r = 20\%{/tex}
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Find compound interest on rs 25000 for 1 and half year at 20% rate compounded half yearly.

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Find out the probability of getting of king from red cards , club cards and face cards in well shuffled deck of cards.

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Ans. Total cards = 52
Total red kings = 2
P(red king) = 2/52 = 1/26
Total Club cards = 13
P(club card) = 13/52 = 1/4
Total Face Card = 12
P(Face card) = 12/52 = 3/13
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In obroi hotel there is enough provision for 90 customers for 20 days , if 30 more customer checked in after 4 days . Find out how many days same provision last.

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Ans. No. of Customers = 90
Food available for days = 20
After 4 days,
No of customers = 90 + 30 = 120
90 Customers ll use food = 16 days
1 customer ll use food = 16*90 = 1440
120 Customers ll use food = 1440/120 = 12 days
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The strangth of class decreased every year at 10%. If strangth of class was 70000 2 year ago . Find present strangth.

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Ans. Strength of class 2 years ago = 70000
Decreasing rate = 10%
Strength after 1 year = {tex}70000  {70000\times 10\over 100} = 700007000{/tex}
=> 63000
Present Strength = {tex}63000  {63000\times 10\over 100} = 630006300{/tex}
=56700
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The strangth of class decreased every year at 10%. If strangth of class was 70000 2 year ago . Find present strangth.

Answers:

Ans. Strength of class 2 years ago = 70000
Decreasing rate = 10%
Strength after 1 year = {tex}70000  {70000\times 10\over 100} = 700007000{/tex}
= 63000
Present Strength = {tex}63000{63000\times 10\over 100} = 630006300{/tex}
=56700
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There has number 1 to 8 find,
1 probabolity of 7
2 even no
3 multiple of 3
4 factor of 28

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Ans. Total number = 8
(1) No of favourable case for 7 = 1
P(7) = 1/8
(2) total even numbers = 4
P(even No) = 4/8 = 1/2
(3) Total multiple of 3 = 2
P(Multiple of 3) = 2/8 = 1/4
(4) Factors of 28 = 2
P(Factor of 28) = 2/8 = 1/4
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Meena drink 3 tins of softdrinks , each tin has base radius 7cm and height 14cm . He threw all tin on ground.
1 Find total softdrinks in cubic cm.
2 advice to be given that the compaign run by govt.

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Ans. Radius of tin = 7cm
Height of tin = 14cm
Volume of tin = {tex}=> \pi r^2h=> {22\over 7}\times 49\times 14 = 2156cm^3{/tex}
(1) As she drinks 3 tin,
Then total volume = 3*2156 = 6468 cm^{3}
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A painter got certain amount and donate 1/4th of it to pm welfare fund. If the dimension of the area is 12×10×10 and rate 10rs/m sq
1. Find total money
2. Find denoted money
3. Value promoted

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A train running a uniform 120km/hr. Find distance covered by train.

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A painter got certain amount and donates 1/4 th of it to welfare fund . If the dimension of area is 10×12×10m and rate 10rs/m sq. Find out total money and denoted money value showned.

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A person has deposited amount at 12%rate . Find out years to make principle double.

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Ans. Let Principal = 100 Rs.
Rate = 12%
Amount = 200 ( as per question)
Interest = 200  100 = 100
Time required = {tex}Interest \times 100 \over Rate \times Principal{/tex}
{tex}=>{ 100\times 100 \over 12\times 100} = {25\over 3} = 8{1\over 3}Years{/tex}
= 8 Years 4 Months
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What is oscillation

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Movement of body in its fix axis by the moving object to and frocalled oscillation.
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To and fro movement of a body around fixed axis is called oscillation.
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A bag has something inside yellow red and black color. If 4y 3r 4b. Find probability of y r and not black.

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Probabilty of yellow = 4/11
probability of red = 3/11
probability of not black = 7/11.
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A boy constructed a big wall with dimensions 8m , 6m ,22.5m. Find out no of bricks required if brick has dimension 25cm , 11.25cm ,6 cm.

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Ans. Volume of Wall = {tex}8\times 6\times 22.5 = 1080 m^3 {/tex}
=> {tex} 1080 \times 10^6 cm^3 {/tex}
Volume of Brick = {tex}25\times 11.25 \times 6 =1687.5 cm^3{/tex}
Number of bricks = {tex}Volume \space of \space Wall \over Volume \space of \space Brick{/tex}
=> {tex} {1080\times 10^6 \over 1687.5} = 64\times 10^4 {/tex}
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To celebrate holi a society has ordered water from municipility . The shape of the tank is rectangle with dimensions 12m ×16m×20m . Find out total water supplied in litre.

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Ans. Dimensions of tank = 12m ×16m×20m
Volume of tank = 12m ×16m×20m= 3840m^{3}
Water Supplied = Volume of Tank = 3840m^{3} = 3840000 L
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A cylindrical shape tank whose base diameter 28m and height 14m find the capacity of water tank in litre.

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Ans. Diameter of base of tank = 28m
Radius of base of tank = 28/2 = 14m
Height of tank = 14m
Volume of tank = {tex}\pi r^2h{/tex}
=> {tex}{22\over 7} \times 196\times 14 = 8624m^3{/tex}
We Know
1m^{3 } = 1000L
So
Volume of tank in L =8624000L
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A train is covers 300 km in 180 minutes . Find the timing to cover 350 km.

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distance(km) time(minutes)
300 180
350 ?
= 350x180 divided by 300
= 63000 divided by 300
= 210 minutes
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A train is moving uniform rate of 70km/hr. Find distance covered in 12 minutes and find the timing to cover 210km.

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Ans Speed of Train = 70Km/h
(i) Time = 12 minutes = {tex}{12\over 60} = {1\over 5}hour{/tex}
Distance = {tex}Speed \times time = 70\times {1\over 5} = 14Km{/tex}
It ll cover 14 Km in 12 minutes.
(ii) Distance = 210 Km
Time = {tex} {Distance \over Speed} = {210\over 70}= 3hour{/tex}
It ll take 3 hours to cover 210Km
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The strangth of class decreased every year at 10%. If strangth of class was 70000 2 year ago . Find present strangth.

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In a ceremony lemon juice is distributed to 50 guests . If radius of glass is 14 cm and height is 7cm then find out the total lemon juice required in cubic cm.

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Ans. No of Guest = 50
Radius of Glass = 14cm
Height of Glass = 7 cm
Volume of Glass =
{tex}{22\over 7}\times 196\times 7 = 4312cm^3{/tex}
Total Volume of Juice = {tex}No\space of \space Guest \times Volume \space of\space Glass{/tex}
=> 50*4312 = 215600 cm^{3}
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A rectangular sheet of paper of length 33 cm and breadth 22cm is folded in 2 ways to form a cylinder. Find the difference in the volumes of cylinder formed.

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