Sam makes bread rolls and gives 2/5 to his neighbor and 4/9 of the remainder to his cousin. he has 15 left. how many did sam make?

So what you can do is subtract 2/5 and 4/9 from 1. 1-2/5 is 3/5. the 3/5-4/9= you have to get a common denominator so it would be 45, so 27/45-20/45 is 7/45. so if 7/45=15 rolls, how many did he make? just do some division, divide both by 7, so 1/45=15/7 or 2 1/15. multiply that by 45 and you will have 93.       SAM MADE 93 ROLLS