No products in the cart.

The traffic lights at three different …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

The traffic lights at three different road crossings change after every 48 seconds, 72 seconds and 108 seconds. If they change simultaneously at 7 AM, after what time will they change again simultaneously
  • 1 answers

Sia ? 3 years, 11 months ago

The traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds, respectively.

So let us take the LCM of the given time that is 48 seconds, 72 seconds, 108 seconds

⇒ 48 = 2 × 2 × 2 × 2 × 3

⇒ 72 = 2 × 2 × 2 × 3 × 3

⇒ 108 = 2 × 2 × 3 × 3 × 3

Hence, LCM of 48, 72 and 108 = (2 × 2 × 2 × 2 × 3 × 3 × 3)

LCM of 48, 72 and 108 = 432

So  after 432 seconds, they will change simultaneously

We know that

60 seconds = 1 minute

so on dividing 432 / 60, we get 7 as quotient and 12 as a reminder

Hence, 432 seconds = 7 min 12 seconds

∴ The time  = 7 a.m. + 7 minutes 12 seconds

Hence, the lights change simultaneously at  7:07:12 a.m

http://mycbseguide.com/examin8/

Related Questions

Venu Gopal has twice
  • 0 answers
(A + B )²
  • 1 answers
X-y=5
  • 1 answers
Find the nature of quadratic equation x^2 +x -5 =0
  • 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