Question Detail

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

1. A motorist travel to a place 150 km away at an avearge speed of 50 km/hr and returns ar 30 km/hr.His average speed for the whole jouney in km/hr is

36.5 km/hr
37.5 km/hr
35.5 km/hr
34.5 km/hr

Answer: Option B

Explanation:

Average speed will be

$\begin{aligned} \frac{2xy}{x+y} km/hr = \frac{2(50)(30)}{50+30} km/hr \end{aligned}$

= 37.5 km/hr

2. A library has an average of 510 visitors on Sundays and 240 on other day. The average number of visitors in a month of 30 days starting with sunday is

Answer: Option B

Explanation:

As the month begin with sunday, so there will be five sundays in the month. So result will be:
$\begin{aligned} = (\frac{510 \times 5 + 240 \times 25}{30}) = (\frac{8550}{30}) = 285 \end{aligned}$

3. 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

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

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. If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is

54.48
54.68
54.60
54.58

Answer: Option B

Explanation:

$\begin{aligned} \frac{(55 \times 50) +(60 \times 55) +(45 \times 60) }{55 + 60 + 45} \end{aligned}$

$\begin{aligned} \frac{8750}{160} = 54.68 \end{aligned}$

Tanvee 11 years ago

If its odd number then we need to to take x,x+1,x+3,x+5.... why we are taking even number?

mastguru 11 years ago replied

Hello Tanvee,
We are taking X as an odd number,
so, other consecutive odd number will be x+2 and another will x+4 and so on..
Lets say 1 is odd number, then next will 1+2 =3, 1+4 =5.. and so on.
In this way we are solving this problem.
Admin 12 years ago

Thanks Nagendar. It was a typing mistake. Question was about four consecutive odd numbers.
We appreciate your feedback.
nagendar 12 years ago

here x is an even number. but you got x=21(which is not even number). so consecutive even numbers are: 2x,2x+2,2x+4,2x+6.