Question

Twenty stamps cost $8.40. How much does it cost to buy 5 stamps? Answers:  A.

$2.10   B. $11.90   C. $4.20   D. $42.00         

Answer 1

20x=8.40
x=0.42

5 stamps or 5x
5x
5(0.42)
=2.1$

Answer 2

5 stamps will cost $$2.10

if twenty stamps cost 8.40, we want to find out how many five stamps cost.

20 ÷ 5 = 4

we can use this to calculate ->

8.40 ÷ 4 = 2.10, which is the price for those five stamps :)