Answer:
10 deliveries
Step-by-step explanation:
Let's make an equation to represent this situation. John makes 12 dollars per delivery and he gets a base of 30 dollars added on no matter how many deliveries he makes.
12d+30=m
where d are the deliveries and m is the money he made. He made 150 dollars, so we can substitute 150 in for m.
12d+30=150
To solve the equation, we want to find out what d is. In order to do this, we have to get d by itself. Perform the opposite of what is being done to the equation. Keep in mind, everything done to one side, has to be done to the other.
30 is being added to 12d. Subtract 30 from both sides, because subtraction is the opposite of addition.
12d+30=150-30
12d=150-30
12d=120
d is being multiplied by 12. The opposite of multiplication is division. Divide both sides by 12.
12d/12=120/12
d=120/12
d=10
John made 10 deliveries
