📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!
  • google app store apple app store
    • ✖

      Question

      The average of twelve numbers is 45.5. The average of

      the first four numbers is 41.5 and that of the next five numbers is 48. The 10th number is 4 more than the 11th number and 9 more than the 12th number. What is the average of the 10th and 12th numbers?
      A 47 Correct Answer Incorrect Answer
      B 46.5 Correct Answer Incorrect Answer
      C 46 Correct Answer Incorrect Answer
      D 47.8 Correct Answer Incorrect Answer

      Solution

      Average of 12 numbers = 45.5 Sum of 12 numbers = 45.5 × 12 = 546 Average of first 4 numbers = 41.5 Sum of first 4 numbers = 41.5 × 4 = 166 Average of next 5 numbers = 48 Sum of next 5 numbers = 48 × 5 = 240 Sum of 10th, 11th and 12th number = 546 – 166 – 240 = 140 Let the 10th number be x. 11th number = x – 4 12th number = x – 9 According to the question, => x + x – 4 + x – 9 = 140 ⇒ 3x – 13 = 140 ⇒ 3x = 140 + 13 ⇒ 3x = 153 ∴ x = 153/3 = 51 Average of 10th and 12th number = (51 + 51 – 9)/2 = 93/2 = 46.5

      Practice Next
      More Average Questions

      Relevant for Exams:

      ask-question