Question

Carl bought 19 apples of 2 different varieties to make a pie.The total cost of the apple was $5.10.Granny Smith apples cost $0.25 each and Gala apples cost $0.30 each.How many of each type of apple did Carl buy?

Answer 1

For this case we propose a system of equations:

x: Let the variable representing the quantity of Granny Smith apples

y: Let the variable representing the number of Gala apples

According to the statement we have:

$x + y = 19\\0.25x + 0.30y = 5.10$

From the first equation we have to:

$x = 19-y$

replacing in the second equation:

$0.25 (19-y) + 0.30y = 5.10\\4.75-0.25y + 0.30y = 5.10\\4.75 + 0.05y = 5.10\\0.05y = 5.10-4.75\\0.05y = 0.35\\y = \frac {0.35} {0.05}\\y = 7$

So, Carl bought 7 Gala apples

On the other hand:

$x = 19-7 = 12$

So, Carl bought 12 Granny Smith apples

Answer:

Carl bought 7 Gala apples and 12 Granny Smith apples