Question

Adam and Bob went apple picking in an orchard. At the end of the day, they counted the number of apples they picked. They realized that if Adam picked 39 more apples, he would have picked twice as many as Bob picked. Also, if Bob picked 39 more apples, he would have picked twice as many as Adam picked. How many apples did Adam and Bob pick all together?

Answer 1

Adam --- x apples
Bob ---- y apples

x+39 = 2y or x - 2y = -39
2x = y + 39 or 2x - y = 39

the first equation: x - 2y = -39
double the 2nd : 4x - 2y = 78
subtract them:
3x = 117
x = 39

into the 2nd:
78 - y = 39
-y = -39
y = 39

They each picked 39 apples.