__Question:__The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg. Find the average weights of all the boys in the class.

**Options:**

A. | 47.55 kg | |

B. | 48 kg | |

C. | 48.55 kg | |

D. | 49.25 kg |

**Answer: Option C**

Required average = \(\left(\frac{50.25\times16+45.15\times8}{16+8}\right)\)

\(=\left(\frac{804+361.20}{24}\right)\)

\(=\frac{1165.20}{24}\)

= 48.55

Check All Quantitative Aptitude Questions (MCQs)

Check All Average Questions (MCQs)

#### Submit Answer & Explaination

## More Questions Related to Quantitative Aptitude > Average :

__Question 1.__The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is:

**Options:**

- 17 kg
- 20 kg
- 26 kg
- 31 kg

**Answer: Option D**

Let A, B, C represent their respective weights. Then, we have:

A + B + C = (45 x 3) = 135 .... (i)

A + B = (40 x 2) = 80 .... (ii)

B + C = (43 x 2) = 86 ....(iii)

Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)

Subtracting (i) from (iv), we get : B = 31.

Threrfore B's weight = 31 kg.

__Question 2.__In Aruns opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest not agree with Arun and he thinks that Aruns weight is greater than 60 kg but less than 70 kg. His mothers view is that his weight cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?

**Options:**

- 67 kg.
- 68 kg.
- 69 kg.
- Data inadequate
- None of these

**Answer: Option A**

Let Arun's weight by X kg.

According to Arun, 65 < X < 72

According to Arun's brother, 60 < X < 70.

According to Arun's mother, X <= 68

The values satisfying all the above conditions are 66, 67 and 68.

Therefore Required average = \(\left(\frac{66+67+68}{3}\right)=\left(\frac{201}{3}\right)=67kg.\)

__Question 3.__A car owner buys petrol at Rs.7.50, Rs. 8 and Rs. 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if he spends Rs. 4000 each year?

**Options:**

- Rs. 7.98
- Rs. 8
- Rs. 8.50
- Rs. 9

**Answer: Option A**

Total quantity of petrol

consumed in 3 years = \(\left(\frac{4000}{7.50}+\frac{4000}{8}+\frac{4000}{8.50}\right)liters\)

\(=4000\left(\frac{2}{15}+\frac{1}{8}+\frac{2}{17}\right)liters\)

\(=\left(\frac{76700}{51}\right)liters\)

Total amount spent = Rs. (3 x 4000) = Rs. 12000.

Therefore Average Cost = Rs.\(\left(\frac{1700\times51}{76700}\right)=Rs.\frac{6120}{767}=Rs.7.98\)

__Question 4.__A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is:

**Options:**

- 250
- 276
- 280
- 285

**Answer: Option D**

Since the month begins with a Sunday, to there will be five Sundays in the month.

Required avarage = \(\left(\frac{510\times5+240\times25}{30}\right)\)

= \(\frac{8550}{30}\)

= 285

__Question 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:

**Options:**

- 53.33
- 54.68
- 55
- None of these

**Answer: Option B**

Required average = \(\left(\frac{55\times50+60\times55+45\times60}{55+60+45}\right) \)

= \(\left(\frac{2750+3300+2700}{160}\right)\)

= \(\frac{8750}{160}\)

= 54.68

__Question 6.__A pupils marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half (1/2). The number of pupils in the class is:

**Options:**

- 10
- 20
- 40
- 73

**Answer: Option C**

Let there be *x* pupils in the class.

Total increase in marks = \(\left(x\times\frac{1}{2}\right)= \frac{1}{2}\)

Therefore \(\frac{x}{2}= \left(83-63\right) \Rightarrow \frac{x}{2}= 20 \Rightarrow x = 40.\)

## Topics

## Recent Questions

**Q.**Find Which One Word Cannot Be Made From The Letters Of The G....

**Q.**Srimathy Borrowed A Sum For 3 Years On S.I. At 10%. The Tot....

**Q.**Which Of The Fowling Currency Of Dubai? ....

**Q.**4.036 Divided By 0.04 Gives: ....

**Q.**Direction To Solve : Find Out The Wrong Term In The Given ....

**Q.**From A Point In The Interior Of An Equilateral Triangle P....

**Q.**The Area Of The Base Of A Right Circular Cone Is 78.5 Cm2....

**Q.**The Ages Of Kamaraj And Deenan Differ By 16 Years, Six Year....

**Q.**Naresh Drives To His Office At 40 Km/h And Returns Along ....

**Q.**Direction To Solve : In Each Of The Following A Sequenc....

**Q.**Two Trains Of Equal Length Are Running On Parallel Lines In ....

**Q.**A, B And C Are Employed To Do A Piece Of Work For Rs 805.....

**Q.**Choose The Exact Meaning Of The Idiomatic Expressions/phrase....

**Q.**Read Each Sentence To Find Out Whether There Is Any Error In....

**Q.**Which State Is Called The Cradle Of Buddhism? ....

**Q.**Coins Of Which Muslim Rulers Bear Image Of Devi Lakshmi ? ....

**Q.**Boston Tea Party Is Associated With?....

**Q.**Which One Of The Following Four Vedas Contains As Account O....

**Q.**Find Which One Word Cannot Be Made From The Letters Of The G....

**Q.**It Is The Study Of Molecules And Structures Whose Size Rang....