Deanna has 5-cent stamps and 10-cent stamps. If she has 100 total stamps, what is the value of the stamps? Call the 5-cent stamps n.
Value of 5-cent stamps
0.05n
Number of 10 cent stamps is:
100 - n
Value is 0.10(100 - n) = 10 - 0.10n
Add them both:
10 - 0.10n + 0.05n
10 - 0.05n
Value of 5-cent stamps
0.05n
Number of 10 cent stamps is:
100 - n
Value is 0.10(100 - n) = 10 - 0.10n
Add them both:
10 - 0.10n + 0.05n
10 - 0.05n