How do you solve 17 and 18 I need explanation pls

17. C

18.G

Step-by-step explanation:

17. According to the question, gravel is 4/13 of the total asphalt substance. One parking lot has 260 tons of asphalt. So this means there is 80 tons of gravel because 260 times 4/13=80. We need to find the tons of gravel if we made 3 parking lot. This means 3 parking lot is the same as 780. So we can just find the measure of gravel by multiplying

4/13 by 780.

So there is 240 tons of gravel. C is the answer.

18. Set up system of equations.

The ratio of a to c is 1:7 and the ratio of b to c is 3:7. Using this information,

Using this info, we can make alternate equations

Subsitue this into the original equation,

We need to find c, c is 7 times more than a so c is

1010: 3030

is it i think