In a two-paper test Meera scored 72 out of 90 in Paper I and 108 out of 150 in Paper II. Taking both papers together, what per cent of the total marks did she score?

Add the marks and the maxima separately: she scored 72 + 108 = 180 out of 90 + 150 = 240, so 180/240 = 0.75 = 75%. 76% is the trap of averaging the two paper percentages (80% and 72%), which is only valid when both papers carry equal marks - here Paper II carries more. 80% and 72% are the individual paper scores.