Question

3 chocolate bars and 4 packets of candy weigh 200 g. 3 chocolate bars and 7 packets of candy weigh 260 g. What is the weight of a chocolate bar?

Answer 1

4P = 200 - 3C

3C + 7P = 260

3C + 7*(200-3C)/4 = 260

Solve for C.

Answer 2

x = weight of a chocolate bar

y = weight of a candy bar

Solve system of equations:

3 x + 7 y = 260
-
3 x + 4 y = 200
____________

3 y = 60

y = 60 / 3 = 20 g

3 x + 4 y = 200

3 x + 4 ∙ 20 = 200

3 x + 80 = 200

3 x = 200 - 80

3 x = 120

x = 120 / 3 = 40

The weight of a chocolate bar = 40 g