Question

John can eat pizza in 4 minutes.jim can eat a pizza in 5 minutes. Their grandfather can eat a pizza in 20 minutes. If two boys and their grandfather all start eating same pizza at the same time,how many seconds does it take then to finding the pizza

Answer 1

John can eat a pizza in 4 minutes.
Jim in 5 mimutes,
And grandpa in 20 minutes.

Together when they eat,
John eats 1/4 th of pizza and jim 1/5 th and grandpa 1/20 th of a pizza in a minute.

Ie,
1/4 + 1/5 + 1/20 = 1/2

Ie,
In a minute they eat 1/2 or half of the pizza.

So they require 2 minutes together to finish the pizza.

So the answer is 2 minutes, or 120 seconds.