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Find the sum of first 30 natural numbers

  • 470
  • 468
  • 465
  • 463

Answer: Option C

Explanation:

Sum of n natural numbers
\begin{aligned}
= \frac{n(n+1)}{2}
\end{aligned}

\begin{aligned}
= \frac{30(30+1)}{2} = \frac{30(31)}{2} = 465
\end{aligned}

Similar Questions :

1. Average of 10 numbers is zero. At most how many numbers may be greater than zero

  • 0
  • 1
  • 5
  • 9

Answer: Option D

2. The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is

  • 40
  • 35
  • 45
  • 55

Answer: Option A

Explanation:

Sum of the present ages of husband, wife and child = (27 * 3 + 3 * 3) years = 90 years.

Sum of the present ages of wife and child = (20 * 2 + 5 * 2) years = 50 years.

Husband's present age = (90 - 50) years = 40 years

3. Find the average of all numbers between 6 and 34 which are divisible by 5

  • 15
  • 20
  • 25
  • 30

Answer: Option B

Explanation:

\begin{aligned}
Average = (\frac{10+15+20+25+30}{5}) = \frac{100}{5} =20
\end{aligned}

4. A batsman makes a score of 87 runs in the 17th match and thus increases his average by 3. Find his average after 17th match

  • 36
  • 37
  • 38
  • 39

Answer: Option D

Explanation:

Let the average after 17th match is x
then the average before 17th match is x-3

so 16(x-3) + 87 = 17x
=> x = 87 - 48 = 39

5. Average age of boys in a class is 16 years and average age of girls is 15 years, what is the average age of all

  • 15.5
  • 15
  • 16
  • Cant be computed

Answer: Option D

Explanation:

As number of girls and boys is not given so result cant be computed

Read more from - Average Questions Answers
Post a comment

  • SOLO 12 years ago

    u have given sum of 30 natural numbers not the avg....

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