SSC CGL – Combined Graduate Level Examination · प्रश्न 58
The average of 15 numbers is 72. The average of the first 6 numbers is 65. The average of the next 5 numbers is 20% higher than the average of the first 6. The 12th number is 8 less than the 15th, the 13th is 5 greater than the 15th, and the 14th number is 78. What is the average of the 12th and 13th numbers?
उत्तर देखें और व्याख्या
उत्तर: (A) 73.5
व्याख्या
Total 1080; first 6 = 390; next 5 = 5 × 78 = 390; last 4 = 300. With the 15th = x: (x − 8) + (x + 5) + 78 + x = 300, so x = 75. Then 67 and 80 average 73.5.