List of top Quantitative Aptitude Questions on Averages asked in NPAT

There are \( n \) numbers. When 50 is subtracted from each of these numbers, the sum of the numbers so obtained is -10. When 46 is subtracted from each of the original \( n \) numbers, then the sum of the numbers so obtained is 70. What is the mean of the original \( n \) numbers?
The sum of the first 15 terms of the series \[ \frac{1}{24} + \frac{1}{104} + \frac{1}{234} + \dots = \frac{a}{b}, \text{ where HCF}(a,b) = 1. \text{ What is the difference between } a \text{ and } b? \]
When 8 is added to each of the given 'n' numbers, the sum of the resulting numbers is 207. When 5 is subtracted from each of the given 'n' numbers, the sum of the resulting numbers is 77. What is the mean of the given 'n' numbers?
When 8 is added to each of the given 'n' numbers, the sum of the resulting numbers is 207. When 5 is subtracted from each of the given 'n' numbers, the sum of the resulting numbers is 77. What is the mean of the given 'n' numbers?