Question

A pack of gum costs 75 cents. That is 3 cents less than three times what the pack cost 20 years ago. Which equation could be used to find the cost of the gum 20 years ago?

A)
0.3x - 0.3 = 0.75
B)
3x - 0.3 = 0.75
C)
3x - 3 = 75
D)
3 - 3x = 75

Answer 1

C

Explanation:

Let the cost of a pack of gum 20 years ago = x cents

Given, present cost of a pack of gum = 75 cents

Given, present cost of a pack of gum is 3 cents less than three times what the pack costs 20 years ago.

So,

`75 + 3 =3x`

`75= 3x -3`

`3x-3=75`

Therefore,

Equation ,
`3x-3=75` , can be used to find the cost of the gum 20 years ago.

Answer 2

20 years ago it costed 3x - 3 = 75 because it costed 3 cents less than (this -3 part) 3 times of its price (price 20 years ago is x, 3 times that is 3x.
thats how we get 3x - 3 and we make it equal to 75 because we are comparing those 2 prices

So, answer is C.