Aisha owns an apparel store. she bought some shirts and jeans from a wholesaler for $3,900. each shirt cost $12 and each pair of jeans cost $28. if she sold the shirts at 70% profit and jeans at 125% profit, her total profit was $3,885. how many shirts and jeans did she buy from the wholesalers?

Let the number of shirts be x, and the jeans be y.

Total cost of shirts = 12x
Total cost of Jeans = 28y

This means that:        12x + 28y = 3900..........(a)

Selling price for Shirts 70% profit, means = 100% + 70% = 170% of the cost price

170/100  * 12x = 1.7*12x = 20.4x 

Selling price for Jeans 125% profit, means = 100% + 125% = 225% of the cost price

225/100  * 28y = 2.25*28y = 63y

Total profit = 3885, remember total cost = 3900

Total selling price = 3885 + 3900 = 7785

20.4x + 63y = 7785..........(b)

12x + 28y = 3900.............(a)

20.4x + 63y = 7785...........(b)

Solving the simultaneous equation with a programmable calculator:

x = 150, y = 75

150 shirts and 75 jeans.

The answer is part a: use