The best approach to these type of questions are to put all the numbers in decimal format and put them all to the same amount of places after the decimal.
- .500 will remain as is
- 9/15 is .6 but to keep them all to the same amount of value we would say .600
- .250 would remain as is
- .750 would remain as is
- 7/8 would equal to .875
And now as you order them least to greatest you will find out that 7/8 would be the largest of them all