Question

With three boys on a large scale, it read 170 pounds. When Adam stepped off, the scale read 100 pounds. When both Adam and Ben stepped off, the scale read 60 pounds. What is the weight of each boy?

Answer 1

Adam = 70 pounds

Ben = 40 pounds

C = 60 pounds

Explanation:

We can work out some equations based on the given information:

We can call the boys A, B and C

so,

• when all three boys are standing on the scale, it reads 170 pounds.

`A + B + C = 170` - Eq(1)

• when Adam stepped off, the scale reads 100. This means that the combined weight of the remaining two boys is 100.

`B + C = 100` - Eq(2)

• when both Adam and Ben stepped off, the weight of the remaining boy is shown on the scale.

`C = 60`

So we already knew the weight of boy C. (it was in the question all along)

`C = 60` pounds

Now to find the individual weights of the remaining boys, we can work our way backwards

we can put this value back in Eq(2), to find the weight of boy B.

`B + C = 100`

`B + 60 = 100`

`B = 100 - 60`

`B = 40`

the

the weight of boy B (Ben) is
`B = 40` pounds

now we can put all of the known weights of the boys in Eq(1) to find the weight of Boy A.

`A + B + C = 170`

`A + 40 + 60 = 170`

`A + 100 = 170`

`A = 170 - 100`

`A = 70`

the weight of boy A (Adam) is
`A = 70` pounds

The Answer:

Adam = 70 pounds

Ben = 40 pounds

C = 60 pounds