Felicity and Adhira took separate trips. Felicity used 5 less gallons of gas than four times the number of gallons that Adhira used for her trip. Together the girls used 30 gallons of gas. How many gallons did Felicity use? Think carefully first, then make a decision:
Let A = Adhira's gallons. Felicity = 4A - 5. 5A - 5 = 30. 5A = 35. A = 7. Felicity used 23 gallons of gas for her trip. So, the answer is 23.