Multiple Choice Questions

The average of twelve numbers is 45 5 The averageof the first four numbers is 41 5 and that of the n...........

Quantitative Aptitude (CGL) Average

The average of twelve numbers is 45.5. The averageof the first four numbers is 41.5 and that of the next five numbers is 48. The

10^thnumberis 4 more than the 11^thnumber and 9 more than the 12^thnumber. Whatis the average of the 10^thand 12^th

numbers?

This questions was previously asked in

SSC CGL 4th March 2020 Shift-1

47.8

46.6

- The average of twelve numbers is 45.5. Thus, their total is 45.5 × 12 = 546.

- The sum of the first four numbers, given their average of 41.5, is 41.5 × 4 = 166.

- The sum of the next five numbers, with an average of 48, is 48 × 5 = 240.

- The sum of the last three numbers (10th, 11th, and 12th) is 546 - (166 + 240) = 140.

- Let 11th number be x. Then, 10th number is x + 4 and 12th number is x - 5.

- Therefore, x + (x + 4) + (x - 5) = 140 simplifies to 3x - 1 = 140.

- Solving for x gives x = 47.

- Thus, the 10th number is 51, and the 12th number is 42.

- The average of the 10th and 12th numbers is (51 + 42) / 2 = 46.5.

- Option:1, 47

- Option:2, 47.8

- Option:3, 46

- Option:4, 46.6

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