10 + 1/2*4*48 => 10 + 2*48 => 10 + 96 = 106.
In linear change, the two variables keep increasing or decreasing at the same speed.
discount per tshirt=(originalprice-discountedprice)/numberofshirtssold
20 tshirts
originaprice=20*p=20p
discountedprice=20p-60
numberofshirtssold=20
discountpershirt=(20p-(20p-60))/20
discountpershirt=(20p-20p+60)/20
discountpershirt=(60)/20
discountpershirt=3
the discount per tshirt is $3.00 per shirt
The answer is b, c, and d
