Question

The average of 9 numbers is 34. If the average of the first 4 numbers is 38 and that of the last 4 is 35, then find the 4th number?

Answer 1

Answer:

The average of 9 numbers is 40 . If the average of first five numbers is 38 and that of the last five numbers is 50,then what is the fifth number?

(1) Avg of 9 numbers = 40. So total of 9 numbers = 9 * 40 = 360.

(2) Avg of first 5 is 38. Total of first 5 is = 5 * 38 = 190.

(3) Avg of last 5 is 50. Total of last 5 is = 5 * 50 = 250.

(4) Total of first 5 plus last 5 = 190 + 250 = 440.

(5) Total of first 4 plus fifth + Total of last 4 plus fifth = 440

(6) Total of all 9 numbers + fifth number = 440.

(7) 360 + fifth number = 440.

(8) Fifth number = 440 - 360 = 80.

Answer: Fifth Number = 80.