Question

9 burgers and 1 doughnut cost $31.30. 3 doughnuts and 6 burgers cost $26.70. Find the cost of 2 burgers.

Answer 1

Answer:

$6.40

Step-by-step explanation:

let d be the cost of 1 doughnut and b the cost of 1 burger.

set up 2 equations and solve for b

9b + d = 31.3 → (1)

6b + 3d = 26.7 → (2)

multiplying (1) by - 3 and adding to (2) will eliminate d

- 27b - 3d = - 93.9 → (3)

add (2) and (3) term by term to eliminate d

- 21b + 0 = - 67.2

- 21b = - 67.2 ( divide both sides by - 21 )

b = 3.2

then

cost of 2 burgers = 2 × $3.20 = $6.40