A delivery truck is transporting boxes of two sizes: large and small. The combined weight of a large box and a small box is 90 pounds. The truck is transporting 50 large boxes and 65 small boxes. If the truck is carrying a total of 4950 pounds in boxes, how much does each type of box weigh?

small = 30 pounds

large = 60 pounds

Step-by-step explanation:

two equations can be derived from the question

x + y = 90 eqn 1

50x + 65y = 4950 eqn 2

x = small box

y = big box

multiply equation 1 by 50

50x + 50y = 4500 eqn 3

subtract equation 3 from 2

15y = 450

y = 30

substitute for y in equation 1

y = 60

answer: 42

use a calculator to find that 845/73 = 11.575

the whole part of the answer is 11. multiply this by 73 to get 11*73 = 803.

subtract that result from 845 to get 845 - 803 = 42

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18