Question

A customer works into a post office to purchase stamps. she purchases a total of 45 stamps. some of the stamps are 49cent stamps and some are 33cents stamps. how many 49cent stamps and how many 33cent stamps did she purchase if the total cost of all the stamps was $17.89

Answer 1

Explanation:Let number of 49 cents =A

Let number of 33 cents=B

A+B=45 equation 1

1 $=100 cents

49 cents =.49 dollar

33 cents=.33 dollar

so .49A+.33B=17.89 equation 2

Add equation 1 and equation 2

since these are simultaneous equations

.49A+.33B=17.89

A+ B=45

so divide equation 2 by 100 we get

49A+33B=1789

A+B =45 multiply equation 1 by 33 on both the sides we get

33A+33B=1485 equation 3

so subtract equation 3 from equation 2 we get

49A+33B=1789 equation 2

33A+33B=1485 equation 3

16A+0 =304

16A=304

A=304/16

A=19

putting nalue of A in equation 1 we get

A+B=45

19+B=45

B=45-19

B=26

so number of 49 cent stamps are 19

and number of 33 cent stamps are 26