Answer:
27 years old
Step-by-step explanation:
Let Alvin's age be x and Elga's age is y:
y - x = 15
x + y = 27
2y = 42 (use elimination method)
y = 21
x = 6 (plug it back into either equation)
Therefore Alvin is 6 and Elga is 27
Step-by-step explanation:
Will bought several books that cost $ 2.50 each and received a $ 2 discount on the total bill. If he paid $ 10.50, how many books did he buy ?
2.50x - 2.00 = 10.50
2.50x = 10.50 + 2.00
2.50x = 12.50
x = 12.50/2.50
x = 5....he bought 5 books
