Question

Lati needs to purchase drinks and snacks for a party. Each drink costs $0.75. Each snack costs $3.28. There is a 7% sales tax on her total purchase. She purchases an equal number of snacks and drinks. How many of each item can Lati purchase if she has $64 dollars to spend?

Answer 1

Let's say the number of drinks Lati buys is x and the number of snacks she buys is y:
(1) x = y
(2) 1.07(0.75x + 3.28y) = 64
(The 1.07 is equivalent to 107%, since she is charged an extra 7% of the total price)

Now substituting (1) into (2) we get:
1.07(0.75x + 3.28x) = 64
1.07*4.03x = 64
4.3121x = 64
x = 64/4.3121 = 14 (rounded down, since she cannot spent more than $64)
Thus she can purchase 14 snacks and 14 drinks