Answer:
H = (P - I ) / B
Step-by-step explanation:
Given that : P = I + HB, where P is the cost of the phone, I is the amount of money he started with, H is the number of hours he babysits, and B is his hourly rate for babysitting.
We need to make H the subject of the formula, this is done by rearranging the formula so that H would be the subject. We just have to apply inverse operation to the equation to do this.
P = I + HB
Subtracting I from both sides:
P - I = I + HB - I
P - I = I - I + HB
P - I = HB
Dividing through by B:
(P - I ) / B = HB / B
H = (P - I ) / B