How much gasoline will it need to go 525 miles ?

105 miles per 3 gallons

ok, ratio and proportion

gallons:miles=3:105

if we want 525 miles, we need x gallons

3:105=x:525
3/105=x/525
1/35=x/525
times both sides by 525
525/35=x
15=x

15 gallons
C is answer