What was the money paid by Jagbir?

Mayank contribution = x others contribution is 2x
So total x+2x= 60
so X (Mayank's contribution) = 20

Mirza contributed = y others contribution is 3y
So total 4y = 60
So y ( Mirza's contribution ) = 15

Little contribution = z so others is 4z
Total 5z = 60
So z (Little's contribution) = 12

So Mayank + Mirza + Little contribution = 20+15+12 = 47.
Balance Jagbir contribution = 60-47 = 13

Can you please provide the explanation how it can be achieved. I am confused.

Thanks

$ 13