RAILWAY EXAMS
SUBJECT: AVERAGE
1. The average of even numbers upto 100 is
(A) 50.5 (B) 50 (C) 49.5 (D) 49
Answer: B
Explanation:
Sum of even numbers 1 to 100
100 = 2 + 4+ 6+ 8+ ……..+ 98 = 50^2
Average = 〖50〗^2/50=50
2. The average of 13 results is 50. If the average of the first seven results is 49 and that of the last seven is 52, the seventh result is
(A) 48 (B) 56 (C) 57 (D) 58
Answer: C
Explanation:
Sum of 13 results = 13 × 50 = 650
Sum of first 7 results = 7 × 49 = 343
Sum of last 7 results = 7 × 52 = 364
7th result = 343 + 364 – 650 = 57
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