Answer: the number of minutes of local calls that you made is 644
the number of minutes of international calls that you made is 208
Step-by-step explanation:
Let x represent the number of minutes of local calls that you made.
Let y represent the number of minutes of international calls that you made.
It cost $.06 per local call and $0.15 per international call you are charged $69.84. This means that
0.06x + 0.15y = 69.84 - - - - - - - - 1
The total number of calls add up to 852 minutes. This means that
x + y = 852
Substituting x = 852 - y into equation 1, it becomes
0.06(852 - y) + 0.15y = 69.84
51.12 - 0.06y + 0.15y = 69.84
- 0.06y + 0.15y = 69.84 - 51.12
0.09y = 18.72
y = 18.72/0.09 = 208
x = 852 - y = 852 - 208
x = 644
