Question

On every third Ivan goes to exercise every fifth day Gavin goes to the gym to exersise what is the first day Ivan and Gavin Will be at the gym on the same day

Answer 1

Here you have two number:

• a=3 -  every third day Ivan goes to the gym to exercise;
• b=5 - every fifth day Gavin goes to the gym to exersise.

In order to find the first day Ivan and Gavin will be at the gym on the same day, you should count the least common multiple LCM(a,b.

Since numbers a and b are prime (3=1·3 and 5=1·5), then

LCM(3,5)=3·5=15.

Answer: the first day when Ivan and Gavin Will be at the gym on the same day is 15th day

Answer 2

They'll be at the gym together on the 15th day.