Meg started her trip with 11½ gallons of gas in her car's tank. she bought an additional 6 4/5 gallons on her trip and arrived back home with 3 3/10 gallons left. how much gas did she use on her trip?

11 1/2+6 4/5 equals? So, you have to make each fraction have the same denominator. So, you would notice that they have in LCD (least common denominator )which is 10. So you're new fractions are 11 5/10+ 6 8/10. 11+6=17. 5/10+8/20=13/10. Which simplified it would be 1 3/10. 17+1 3/10 equals 18 3/10. 18 3/10 -3 3/10 equals 15. 15 is the answer.