Arnés car used 100 cups of gasoline during a drive. he paid $3.12 per gallon for gas. how much did the gas cost?

First, we basically just have to see how many gallons 100 cups is.
1 gallon has 16 cups
100 / 16 = 6.25
6.25 = 6 and 1/4

So, Arnes bought 6 and 1/4 gallons of gas.

WHERE 'x' IS HOW MUCH THE GAS COST:

1 / (3.12) = (6.25) / x
1x = (6.25)(3.12)
x = 19.50

So, the gas cost Arnes $19.50

3.12x0.134=0.41808 i think this is how you do it