Question

Janet weighs 20 pounds more than Anna. If the sum of their weights is 250 pounds, how much does each girl weigh?

Answer 1

Janet = J
Anna = A

J = A + 20
J + A = 250

Considering that Janet and Anna are relatively close to eachother in weight, let's divide the sum by 2 to give us a general idea of where their weight lies.

250 / 2 = 125

Janet's and Anna's weights are around 125.
Let's try 140 for Janet and 120 for Anna

140 = 120 + 20 (J = A + 20), this works!
140 + 120 = 260 (J + A = 250), this unfortunately doesn't work.

Let's try 135 for Janet and 115 for Anna.

135 = 115 + 20 (J = A + 20), this works!
135 + 115 (J + A = 250), this also works!

Janet weighs 135 pounds, and Anna weighs 115 pounds.

I hope this helps!

Answer 2

The weight of Anna is: 115 pounds

and the weight of Janet is: 135 pounds.

Explanation:

It is given that:

Janet weighs 20 pounds more than Anna.

This means if the weight of Anna is: x pounds

Then the age of Janet is: (x+20) pounds.

Also,

The sum of their weights is 250 pounds.

i.e.

x+x+20=250

i.e.

2x+20=250

On subtracting both side by 20 we have:

2x=250-20

i.e.

2x=230

On dividing both side by 2 we have:

x=115

Hence, the weight of Anna is:115 pounds.

and the weight of Janet is: 115+20=135 pounds.