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Q:

In a village the average age of n people is 42 years. But after the verification it was found that the age of a person had been  considered 20 years less than the actual age, so the new average, after the correction,increased by 1. The value of n is :

A) 21 B) 20
C) 22 D) None of these

Answer:   B) 20

Explanation:

It is the same as a person with 20 years more age  replaces an existing person of the group ( or village)

Since the total age of the village having n persons, is being increased by 20 years and the average age of village is being increased by 1 year, hence there are total 20 people in the village.

 

Alternatively :  ( n x 42 ) + 20 = ( n x 43 )

                          => n=20

Q:

In a cinema hall for the matinee show which started at 2.30 pm and ended at 5.30 pm the vehicle parking lot had only three wheelers (auto rickshaws) and four wheelers. Today the wheels of the vehicles parked was counted and found to be 240. What could be the number of three wheelers parked therein ?

A) 48 B) 41
C) 45 D) 43
 
Answer & Explanation Answer: A) 48

Explanation:

3X + 4y = 240
by substitute through options 48 is correct

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1 64
Q:

The average of a non-zero number and its square is 11 times the number. The number is ?

A) 22 B) 21
C) 11 D) 17
 
Answer & Explanation Answer: A) 22

Explanation:

Let the number be 'x'.

= 11x
= 22x
=> x = 22.

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2 73
Q:

The ratio of speeds of a car, a train and a bus is 5:9:4. The average speed of the car, the bus and the train is 72 km/hr together. What is the average speed of the car and the train together ?

A) 84 km/hr B) 96 km/hr
C) 72 km/hr D) 60 km/hr
 
Answer & Explanation Answer: A) 84 km/hr

Explanation:

Let the speeds of the car, train and bus be 5x, 9x and 4x km/hr respectively.
Average speed = 5x + 9x + 4x/3 = 18x /3 = 6x km/hr.
Also, 6x = 72 => x = 12 km/hr
Therefore, the average speed of the car and train together is = = 7x = 7 x 12 = 84 km/hr.

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6 63
Q:

When all the students in a school are made to stand in rows of 54, 30 such rows are formed. If the students are made to stand in rows of 45, how many such rows will be formed ?

A) 22 B) 36
C) 32 D) 26
 
Answer & Explanation Answer: B) 36

Explanation:

Total number of students = 54 x 30
When arranged in rows of 45, number of rows formed are,
= 36.

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3 68
Q:

20 men went to a restaurant. Ninteen of them paid Rs.70 each and the twentieth man paid Rs.90.25 more than the average of all the 20 men. What is the total bill ?

A) Rs. 1495 B) Rs. 548
C) Rs. 850 D) Rs. 1750
 
Answer & Explanation Answer: A) Rs. 1495

Explanation:

Let the average bill paid by twenty members = 'x'

But 19 men paid each = Rs. 70

20th man paid Rs. 90.25 more than the avg bill of 20 = x + 90.25

20x = 19(70) + x + 90.25
19x = 1330 + 90.25
19x = 1420.25
x = 1420.25/19 = Rs. 74.75

But the total bill = 20 x 74.75 = Rs. 1495.

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