Ashley's score was 20% higher than Bert's score. Bert's score was 20% lower than Charles Score.
Is Ashley's score greater than Charles Score?
This is essentially a GRE question however my mind can not get around it essentially the answer is that Charles has a higher score than Ashley. Which does not make sense to me. If I apply assigning values to each of the 3 people lets say Ashley has a score 100 which is 20% higher than Bert making Bert's score 80 whereas Bert's score is 20% lower so Charles score should be 96. However I figured out how to solve it which was assigning a value to Charles rather than Ashley but the question is why.
Using your example, Let Ashley's score=100. Ashley's score is 20% > Bert's score. $$ Bert\times 1.2= Ashley.$$ $$Bert \times 1.2 = 100$$ $$ Bert = \frac{100}{1.2}=83.3333$$
Now Bert is 20% less than Charles. So $$Charles - 0.2\times Charles = Bert$$ $$Charles(1-0.2)=Bert$$ $$Charles=\frac{Bert}{0.8}=\frac{83.3333}{.8}=104.16666$$
Clearly with these numbers, there is some rounding error, but
Check;
Ashley is 20% > Bert:$\qquad$ $83.3333\times .2 +83.3333\approx 100$
Bert is 20% < Charles $\qquad$ $104.16666 - .2\times 104.16666 \approx 83.3333$