Quantitative Aptitude • Ratio, Average & MixtureHard
The average of 7 results is 35. The average of the first 4 results is 32 and the average of the last 4 results is 30. What is the 4th result?
A. 38
B. 31
C. 3✓ Correct Answer
D. 35
💡 Solution & Explanation
The first 4 and the last 4 results together make 8 results, but there are only 7: the 4th result is counted in both groups. Sum of the first 4 = 4 × 32 = 128; sum of the last 4 = 4 × 30 = 120; sum of all 7 = 7 × 35 = 245. So the 4th result = 128 + 120 − 245 = 3.
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