InterviewSolution
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Rakesh calculated the average of 7 numbers as 27. The average of the first two numbers is 9 and that of the next two numbers is 14. If the fifth number is twice the sixth one and the sixth number is 50% more than the seventh number, then find the seventh number. 1. 782. 263. 394. 65 |
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Answer» Correct Answer - Option 2 : 26 Given: Average of 7 numbers = 27 Average of first two numbers = 9 Average of next two numbers = 14 Formula Used: Average = Sum of terms/Number of terms Calculations: Let fifth, sixth and seventh numbers be x, y, z respectively. As x is twice of y and y is 50% more than z. ⇒ x : y = 6 : 3, y : z = 3 : 2 ⇒ x : y : z = 6 : 3 : 2 Total sum of 7 terms = 7 × 27 = 189 Sum of first 2 terms = 9 × 2 = 18 Sum of next 2 terms = 14 × 2 = 28 Total sum = Sum of first 2 terms + Sum of next 2 terms + x + y + z ⇒ 189 = 18 + 28 + x + y + z ⇒ x + y + z = 143 1 unit = 130/(x + y + z) = 143/11 ⇒ 1 unit = 13 ⇒ x = 6 × 13 = 78 y = 3 × 13 = 39 z = 2 × 13 = 26 ∴ The value of seventh number is 26. |
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