Answer:
The important clue here is when they say both The girls owe the same amount so what they mean is equate both the functions
so we get
150 - 20n = 130 - 15n
Now n gives us the number of weeks so solve for n
20n - 15n = 150 - 130
5n = 20
n = 4
Now check your solution
150-20(4) = 70
130 - 15(4) = 70
So our answer checks out after 4 weeks both girls who their dads the same amount of money .
Explanation: