Find the missing side or angle measure

Asmall foreign car gete 42 miles per gallon and user 35 gallons on a trip. gasoline costs $1.05 per gallon. what was the cost of gasoline per mile driver?

Write the expression as a constant , a single trigonometric function, or a power of a trigonometric function. sin x cos x/ tan x

If 20% of a number is 35, what is 50% of that number?