Question

Tina paid $6.60 for some $0.15 stamps and some $0.20 stamps. She bought 37 stamps in all. How many of each kind did she buy?

PLS HELP

Answer 1

1 set of A= $0.15

1 set of B= $0.20

Total Stamps bought = 37

Total purchase = 37

Let X= Set A of $0.15 each

Y= Set B of $0.20 each

x+y = 37----------X=37-Y

0.15X + 0.20Y = 6.60

0.15(37-Y) + 0.20Y = 6.60

5.55- 0.15Y + 0.20Y =6.60

0.05 Y = 6.60-5. 55

Y=1.05/ 0.05= 21

X= 37-21= 16