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See all →- The average of five consecutive odd numbers is 47. What is the largest of these numbers? Answer: B. 51 Answer: (B) 51 For consecutive odd numbers the average is the middle number, 47. The numbers are 43, 45, 47, 49, 51, so the la... 1
- The average of 11 numbers is 36. The average of the first six numbers is 32 and that of the last six numbers is 40. What is the sixth number? Answer: D. 36 Answer: (D) 36 The 6th number is counted in both groups. Sixth = 6 × 32 + 6 × 40 - 11 × 36 = 192 + 240 - 396 = 36 . 1
- The average age of 30 students in a class is 14 years. When the teacher's age is included, the average becomes 15 years. What is the teacher's age? Answer: B. 45 years Answer: (B) 45 years Teacher's age = 31 × 15 - 30 × 14 = 465 - 420 = 45 years. 1
- The average weight of 20 students is 45 kg. When the teacher's weight is included, the average increases by 1 kg. What is the teacher's weight (in kg)? Answer: B. 66 Answer: (B) 66 New total = 21 × 46 = 966 kg; old total = 900 kg. Teacher = 66 kg. 1
- The average of five numbers is 42. When one number is removed, the average of the remaining four numbers becomes 40. What is the number removed? Answer: D. 50 Answer: (D) 50 Sum of five = 210, sum of four = 160. Removed number = 210 − 160 = 50. 1
- The average of 13 results is 40. The average of the first seven is 38 and the average of the last seven is 43. What is the seventh result? Answer: A. 47 Answer: (A) 47 The seventh result is counted in both groups of seven. Seventh = 7 × 38 + 7 × 43 − 13 × 40 = 266 + 301 − 520 =... 1