Question

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

$\frac{4x}{4} = \frac{54}{4}$

x = 13.5

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

Hope it will help :)