HELPPP PLEASEE URGENT
A grocery store is offering a promotion where a customer receives a $0.15 discount per item on selected sale items, and Paulo has a coupon where he receives $0.10 off regularly priced items.

Before applying the discounts, the cost of Paulo's sale items was $50.77 and the cost of Paulo's regularly priced items was $40.77. After applying the discounts, Paulo spent $85.49 on both the sale items and regularly priced items.

If Paulo bought 7 more sale items than regular items, how many items did he buy in all?
A. 47
B. 34
C. 27
D. 20

The total cost of the items ($85.49) is the addition of the cost of sale items ($50.77), the cost of regular items ($40.77) and the subtraction of the discount received in sale items (x*$0.15) and the discount received in regular items (y*$0.1). Mathematically:

85.49 = 50.77 + 40.77 - y*0.1 - x*0.15 (eq. 1)

Also, we know that he bought 7 more sale items than regular items, that is:

x = y + 7 (eq. 2)

Replacing eq. 2 into eq. 1 and solving for y:

85.49 = 50.77 + 40.77 - y*0.1 - (y + 7)*0.15

85.49 = 50.77 + 40.77 - y*0.1 - y*0.15 - 1.05

85.49 - 50.77 - 40.77 + 1.05 = -0.25*y

-5 = -0.25*y

y = (-5)/(-0.25)

y = 20

Therefore:

x = 20 + 7 = 27

which makes a total of 20 + 27 = 47 items