Question

A school wants to buy some new desks and chairs. If it buys 40 desks and 100 chairs, the total cost is 1100; if it buy 50 desks and 80 chairs, the total cost is 1150. What is the price of a desk and chair?

Answer 1

40d + 100c = 1100

50d + 80 c = 1150

-1.25*(50d+80c)= 1150*-1.25

-62.5d - 100c = -1437.5

    40d + 100c = 1100

-62.5d - 100c = -1437.5

-22.5d = -337.5

d = -337.5/-22.5

d = 15

50d + 80c = 1150

(50*15) + 80c = 1150

750 + 80c = 1150

80c = 1150-750

80c = 400

c = 400/80

c = 5

Answer:

The price is:

Chair: 5

Desk: 15