On a recent test, Kevin scored m percent higher than the class average, while Katherine scored n percent higher than the class average. What was the class average?
(1) n – m = 7
(2) m = 12
Thanks & Regards
1) We do not get any useful data from this. Obviously insufficient.
2) We do not get any useful data from this. Obviously insufficient.
1 & 2 together. m = 12% and n = 19%. We still do not have any idea about the class average. Insufficient.
I find it hard to explain why 1 & 2 are "obviously" insufficient. If you could tell me how one could think them to be sufficient, I'll try my best to provide an explanation.
We need a starting point (a score) in order to be able to deduce actual numbers from percentages.
It's the classic "given a percentage, find the number" type of question I think. Hence, obviously
we can't deduce anything from 1+2.