Question

A pack of gum costs 50 cents. That is 4 cents less than four times what the pack cost 15 years ago.

Write an equation that could be used to find the cost of the gum 15 years ago.

Then solve and find the price of gum 15 years ago

Answer 1

y = (x+4)/4 where y represents the amount fifteen years ago and x represents the current price.

y = (50+4)/4
y = 13.5

Answer 2

Alright, lets get started.

Suppose the cost of the gum 15 years ago is = x

Today's cost is 4 cents less than four times what the pack cost 15 years ago.

Means

todays cost =
`4 x- 4`

`4x - 4 = 50` ......................equation

Adding 4 in both sides

`4x - 4 + 4 = 50 + 4`

`4x = 54`

Dividing 4 in both sides

`(4x)/(4) = (54)/(4)`

x = 13.5

Hence price of gum 15 years ago was 13.5 cents. : Answer

Hope it will help :)