Barry’s mountain bike weighs 6 pounds more than Andy’s.

If their bikes weigh 42 pounds altogether, how much does Barry’s bike weigh?

If we let A represent the weight in pounds of Andys bike then A+6 will represent the weight in pounds of Barry's bike

a+(a+6)=42

Solve for A.

(A.) 18

(B.) 24

(C.) 6

(D.) 40​