Which number is a common denominator for 3/4 and 3/5

Suzanne began a trip with 18 1/2 gallons of gas in the gas tank of her car if she hughes 17 3/4 gallons on the trip how many gallons does she have left once she finish the trip

Brad earns $12.75/hr and works 40 hours a week. what is his gross annual income?

Write the ratio as a fraction in lowest terms 1 1/3 to 1 2/3