Dolls cost $140 per carton, and trucks cost $430 per carton. if an order comes in for a total of 100 cartons for $28,500, what was the number of cartons of dolls? (hint: let t = cartons of dolls.) 50

Let
 t = cartons of dolls
 r = cartons of trucks
 We have the following system of equations:
 t + r = 100
 140t + 430r = 28500
 We solve the system:
 Step 1:
 -430t + -430r = -43000
 140t + 430r = 28500
 Step 2:
 -290t = -14500
 Step 3:
 t = -14500 / -290
 t = 50
 
 The number of cartons of dolls was:
 t = 50

These time are hard.
(lights cigarette)