Question

Mildred bought 2-cent stamps, 4-cent stamps, and 5-cent stamps for $4.35. The number of 2-cent stamps exceeded the number of 5 cent stamps by 50. The number of 4-cent stamps was 10 less than twice the number of 5-cent stamps. How many of each kind did she buy?

Answer 1

5 cent = 0.05x

2 cent  = 0.02(x+50)

4 cent = 0.04(2x-10)

 

0.05x + 0.02(x+50) + 0.04(2x-10)

0.05x + 0.02x +1 + 0.08x -0.4 = 4.35

0.15x +0.6 = 4.35

0.15x = 3.75

X = 3.75 / 0.15 = 25

 25 5 cent stamps ( 25*0.05 = 1.25)

25+50 = 75 2 cent stamps ( 75*0.02 = 1.50)

2*25 =50-10 = 40 4 cent stamps ( 40*0.04 =1.60)

 

1.25 + 1.50 +1.60 = 4.35

5 cent = 25

2 cent = 75

4 cent = 40