Amir started a business with john and jack. Amir invested 2/6 of the amount to start a business. John 2/5 of the investment. The amount put in by john was 6000.

What is the fraction by jack?

What was the total amount invested by all three?

First, we need to add 2/6 and 2/5.

2/6 can be simplified to 1/3

We need to have 1/3 and 2/5 have the same denominator. 3 and 5's LCM (least common multiply) is 15.

Multiply both the numerator and denominator of 1/3 by 5. This equals 5/15.

Multiply both the numerator and denominator of 2/5 by 3. This equals 6/15.

5/15 plus 6/15 is 11/15. This means that Jack's 6000 dollars is 4/15.

Let's say that x is the total amount invested by all three.

6000/x would equal 4/15.

Solve this by multiply 6000 by 15 and 4 by x and making these two equal each other.

90000 would equal 4x. Divide both sides by 4 to get x.

90000 divided by 4 would be 22500.

4/15 is the fraction by Jack

22500 is the total amount invested by all 3