Question 857916
Y + X = 15 [Marcos had 15 coins in nickels and quarters.]
Y = X + 3 [He had 3 more quarters than nickels.]
Substitute the value of X in the second equation into the first.
(X+3) + X = 15
2X + 3 = 15
2X = 12
X = 6
.
If X is 6, then Y is 9.