Multiple choice

The radius of a cylinder is 40 cm. and a rope can be wrap 60 times on this. If the radius of the cylinder is 30 cm, then how many times it can be wrapped on this?

  1. $80$
  2. $90$
  3. $60$
  4. $45$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rope length = circumference × wraps. If radius decreases from 40 to 30 (factor of 3/4), circumference decreases by 3/4, so wraps must increase by reciprocal 4/3. 60 × 4/3 = 80 wraps. Inverse proportion: more wraps on smaller radius.

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