A weight lifter uses both 2 kg blocks as well as....

Question

A weight lifter uses both 2 kg blocks as well as 5 kg blocks to set up the weighing bar. He has a total of 30 blocks. If the total weight of the bar is observed to be 120 kg, then calculate the number of 5 kg blocks and 2 kg blocks.

Answer 1

Let x be the number of the 2Kg blocks and y be the number of the 5 Kg blocks.

x+y=30

y = 30-x

2x+5y = 120

2x+5(30-x)=120

2x+150-5x=120

3x=30

x=30/3 = 10

y = 30-10 = 20.

There are 20 5Kg blocks and 10 2Kg blocks.