I think there is a mistake in your approach ..

We need not take the average for all the years but only for 1984 as it is clearly mentioned in the question ..

Therefore it would go somewhat like .49 × 10000 = 4900

.37 × 10000 = 3700

4900-3700 = 1200

1200/4900*100 = 25% approx.

Ans (C)

amanvermagmat wrote:

For Subcompact car, we can observe that out of the five values,

2 values are exactly 0.4

1 value is 0.35

2 values are between 0.3 and 0.35

So the average will be approx 0.35 or 0.36

For midsize car,

4 values are between 0.45 and 0.5

1 value is about 0.55

So the average will be approx 0.47 or 0.48

So taking the two answers are 0.36 and 0.48:

Required percentage = (0.48-0.36)/0.48 * 100 = 25%

Hence answer is C

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