Question

a man used $3 to pay for 16 postage stamps. x of them are 15 cents each and the rest are 20 cents each. a) Write down an equation in terms of x and find the value of x. b) is the man supposed to receive and change? If so, find the amount

Answer 1

Explanation:

x = 15 cent stamps

y = 20 cent stamps

I will be using these equations

x + y = 16

0.15x + 0.20y = 3

x = 16 - y

0.15(16 - y) + 0.20y = 3

2.40 - 0.15y + 0.20y = 3

-0.15y + 0.20y = 3 - 2.40

0.05y = 0.60

y = 0.60/0.05

y = 12.......there were 12 twenty cent stamps

x + y = 16

x + 12 = 16

x = 16 - 12

x = 4.....there were 4 fifteen cent stamps

no change is received