I did process of elimination and for each option subtracted one from the current values to see if one was 8x the other. A - 24 & 4 (6x) B - 80 & 8 (10x) C - 48 & 6 (8x) D - 35 & 5 (7x)
If you think about it in a real life scenario, if one person does the job and then another person does the same job at the same speed wouldn't it be the same time? But if its not i think it would be 15 minutes because 45-30 = 15