What is x, the number of cards in Austin's card collection?

Question

Robbie and Austin have started collecting sports cards. 

1. The number of cards that Austin has can be represented by x. 
2. The number of cards that Robbie has is 17 more than two times the number of cards that Austin has.
3. The total number of sports cards in both collections is 71. 

Answer 1

y= 17+2x

x+y = 71

y = 71-x = 17+2x

2x+x = 71-17

3x = 54

x=54/3

x = 18 for austin

y=71-18

y = 53 for robbie