Question

A gym has 2kg and 5kg weights. There are 10 disks in all. The total weight of 2kg and 5kg disks is equal to 29kg. Find the number of disks of each kind in the gym.

Answer 1

no of 5 kg disks is 3, and no of 2 kg disks is (10-3) i.e. 7

Explanation:

Let the no of 2kg disks be a.

Let no of 5 kg disks be b.

2a+5b=29

a+b=10

Using substitution, we have

2(10-b) + 5b=29

20-2b+5b=29

20+3b=29

3b=9

b=3

So no of 5 kg disks is 3, and no of 2 kg disks is (10-3) i.e. 7