The number of 15c stamps is four less than three times the number of 18c stamps. value of all the stamps is S1.29. How many 15c stamps are in the drawer?

Question

Application Problem of system of equations.

Answer 1

n = number of 0.18 stamps

3n - 4 = number of 0.15 stamps

 

0.15(3n - 4) + 0.18n = 1.29

 

0.63n = 1.89

 

n = 1.89/0.63 = 3

 

There are 3 of the 0.18 stamps.

 

3n - 4 = 3(3) - 4 = 5

 

There are 5 of the 0.15 stamps.