Question Detail

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

Answer: Option B

Explanation:

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

1. 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

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

Answer: Option D

3. Marks of a student were wrongly entered in computer as 83, actual marks of that student were 63. Due to this mistake average marks of whole class got increased by half (1/2). Find the total number of students in that class.

Answer: Option D

Explanation:

Suppose total number of students are = X
\begin{aligned}
Total increase = x*\frac{1}{2} = \frac{x}{2} \\
=> \frac{x}{2} = 83-63 = 20 \\
=> x = 40
\end{aligned}

4. The average of four consecutive odd numbers is 24. Find the largest number.

Answer: Option B

Explanation:

Let the numbers are x, x+2, x+4, x+6, then
\begin{aligned}
=> \frac{x+(x+2)+(x+4)+(x+6)}{4} = 24
\end{aligned}

\begin{aligned}
=> \frac{4x+12)}{4} = 24
\end{aligned}

\begin{aligned}
=> x+3 = 24 => x = 21
\end{aligned}

So largest number is 21 + 6 = 27

5. Average of first five multiples of 3 is

Answer: Option A

Explanation:

\begin{aligned}
Average = \frac{3(1+2+3+4+5)}{5} = \frac{45}{5} = 9
\end{aligned}