Question

for a school band trip, marcia decides to order t-shirts for all of the participants. it will cost $4 per shirt for the medium size, and $5 per shirt for the large size. marcia orders a total of 70 t-shirts and spends $320. how many are medium shirts?

Answer 1

30 medium sized t-shirts

Explanation:

Let the number of medium shirts be x and the number of large sized t-shirts be y.

Hence, according to the question,

1 medium t-shirt costs = 4 USD

x medium t-shirt costs = 4*x USD = 4x USD

Also,

1 large t-shirt costs = 4 USD

y large t-shirt costs = 4*y USD = 4y USD

BTP,of course what Marcia spends, would be the cost of the shirts irrespective of discount.

4x+5y = 320 ..1

Also,

x+ y = 70 ..2

Multiplying Eqn 2 by 5,

5x + 5y = 350..3

Subtracting eqn 1 from eqn 3,

5x + 5y = 350

(-) 4x+5y = 320

-------------------------

x = 30(Common 5y cancel out)

Hence, the medium sized t-shirts numbered 30.

Answer 2

x = 30 medium shirts

Explanation:

x + y = 70

4x + 5y = 320

-4x - 4y = -280

4x + 5y = 320

y = 40 large shirts

x + 40 = 70

x = 30 medium shirts