No products in the cart.

Find the sum of all multiples …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

Find the sum of all multiples of 7 lying between 500 to 900
  • 1 answers

Sia ? 6 years, 4 months ago

All multiples of 7 lying between 500 and 900 are
504,511,518,...,896
This is an AP in which a = 504, d=7 and l = 896.
Let the given AP contain n terms. Then,
Tn = 896 {tex}\Rightarrow{/tex} a + (n - 1)d = 896 {tex}\Rightarrow{/tex}504 + (n -1) {tex}\times{/tex} 7 = 896 {tex}\Rightarrow{/tex}497 + 7n = 896
{tex}\Rightarrow{/tex}7n = 399 {tex}\Rightarrow{/tex}n = 57.
{tex}\therefore{/tex}required sum = {tex}\frac{n}{2}{/tex}(a + l)
={tex}\frac{{57}}{2}{/tex}{tex}\cdot{/tex}(504 + 896) = ({tex}\frac{{57}}{2}{/tex}{tex}\times{/tex}1400) = 39900.
Hence, the required sum is 39900.

https://examin8.com Test

Related Questions

(A + B )²
  • 1 answers
Prove that root 8 is an irration number
  • 2 answers
Find the nature of quadratic equation x^2 +x -5 =0
  • 0 answers
X-y=5
  • 1 answers
Venu Gopal has twice
  • 0 answers
sin60° cos 30°+ cos60° sin 30°
  • 2 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App