Question

Sandra and Peter together weigh 275 pounds. Sandra and

Martin together weigh 245 pounds. All three together
weigh 410 pounds. What is Sandra's weight alone?

Answer 1

110 pounds

Explanation:

Let the weight of Sandra, Peter and Martin be S, P and M pounds respectively.

S +P= 275 -----(1)

S +M= 245 -----(2)

S +P +M= 410 -----(3)

(3) -(1):

S +P +M -(S +P)= 410 -275

S +P +M -S -P= 135

M= 135

Substitute M= 135 into (2):

S +135= 245

S= 245 -135

S= 110

Thus, Sarah weighs 110 pounds.