Question

The cost C (in dollars) of making solar powered water fountains for cats, f, is shown in the equation C=30f+170.

How many water fountains can be made when the cost is $770?
Write the verbal statement as an equation.

Answer 1

20 water fountains can be made when the cost is 770.

Verbal statement: The cost equals 30 times the fountains for cats plus 170

Explanation:

Lets review the defined variables.

f = fountains for cats

C = cost

We are given the value of the cost, but not the amount of fountains for cats. This means we will have to solve for f in the equation.

Substitute 770 for C

`770=30f+170`

Subtract 170 on both sides

`600=30f`

Divide by 30

`20=f`

20 water fountains can be made when the cost is 770.

To prove this, plug our numbers into the expression.

`30(20)+170`

`600+170`

`770`

So our answer is correct.

Answer 2

To find how many water fountains can be made when the cost is $770, we can set the cost equation equal to 770 and solve for f:

C = 30f + 170
770 = 30f + 170
600 = 30f
f = 20

Therefore, 20 water fountains can be made when the cost is $770.

Verbal statement as an equation: Cost equals 30 times the number of water fountains plus 170, or C = 30f + 170.
20