Question
What is the average of the squares of the first 31 natural
numbers?Solution
Sum of squares of first 'n' natural numbers = n × (n + 1) × (2n + 1) ÷ 6
So, average = n × (n + 1) × (2n + 1) ÷ 6n = (n + 1) × (2n + 1) ÷ 6
= (31 + 1) × (2 × 31 + 1) ÷ 6
= 32 × 63 ÷ 6
= 336
In the each question, the given two series following the same pattern, then find the pattern used in the 1st series and use the pattern to find the unkn...
12, 26, 54, 96, 150, 222, 306
Calculate Tina's age five years ago given that the current average age of Tina, Rohan, and Ramu is 25 years, while the average age of Rohan and Ramu alo...
The value of integration of log x / x2 is:
A trader cheats by using a weighing scale that shows 1 kg while actually giving only 900 grams. He also marks up the goods by 25% and then gives a 10% d...
The mean of 5 observations is 10 and their standard deviation is 4. Each observation is multiplied by 3 and then increased by 5. Find the new mean and t...
What is the function of the "IF" function in Excel?
Which of the following matrices is both symmetric and skew-symmetric?
Puneet owns 66 foldable laptops, and Raja has 22 more foldable laptops than Puneet. The ratio of foldable laptops between Raja an...
Relevant for Exams:
