Question

1 pizza costs £3.20 more than a bottle of coke. The total cost of the items is £19.40 for 3 pizzas and 1 bottle of coke

Answer 1

1 pizza should cost $5.65

Pizza is $5.65 then bottle of coke is $2.45

3 pizzas and coke: ($5.65*3) + $2.45 = $19.4

I solved this by setting up and solving a system of linear equations:

Variables: p = pizza, c = coke

p = c+3.2

3p+c = 19.4

Solve by substitution

3(c+3.2) + c = 19.4

4c+9.6 = 19.4

c = 2.45

Re-plug in:

p = 2.45+3.2

p = 5.65