1
Q:

Amithab's average expenditure for the January to June is Rs. 4200 and he spends Rs.1200 in January and Rs.1500 in july.The average expenditure for the months of febraury to July is:

A) Rs. 4250 B) Rs. 4520
C) Rs. 4060 D) None of these

Answer:   A) Rs. 4250



Explanation:

Amithab's total expenditure for Jan - June  = 4200 x 6 = 25200

Expenditure for Feb - June = 25200-1200 = 24000

Expenditure for the months of Feb - July = 24000 + 1500 =25500

The average expenditure = \inline \frac{25500}{6}=4250

Q:

The average age of a class is 19 years. While the average age of girls is 18 and that of boys is 21. If the number of girls in the class is 16, Find the number of Boys in the class?

A) 12 B) 10
C) 8 D) 6
 
Answer & Explanation Answer: C) 8

Explanation:

Let the number of boys = x

From the given data,

=> [21x + 16(18)]/(x+16) = 19

=> 21x - 19x = 19(16) - 16(18)

=> 2x = 16

=> x = 8

Therefore, the number of boys in the class = 8.

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3 152
Q:

The mean of 100 observations is 40. It is found that an observation 84 was misread as 48. Then the correct mean is ?

A) 40.36 B) 41.24
C) 41.92 D) 42.05
 
Answer & Explanation Answer: A) 40.36

Explanation:

Given,

mean of 100 observations is 40

=> Total of 100 observations = 40 x 100 = 4000

84 is misread as 48

=> Difference = 84 - 48 = 36

=> Now, new total of 100 observations = 4000 + 36 = 4036

Correct Mean = 4036/100 = 40.36

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9 375
Q:

The average marks of a student in 7 subjects is 85. His average marks in 6 subjects except English is 83. What is his marks in English ?

A) 97 B) 98
C) 92 D) 93
 
Answer & Explanation Answer: A) 97

Explanation:

Marks in English  = 85×7 – 83×6

= 595 – 498

= 97

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13 580
Q:

Navaneet has thrice the money Poonam has and Poonam has 25% more money than Hebah. If the average money of the three is Rs. 350, What is the amount that Navaneet has ?

A) Rs. 175 B) Rs. 220.75
C) Rs. 218.55 D) Rs. 656.25
 
Answer & Explanation Answer: D) Rs. 656.25

Explanation:

Assume Hebah has Rs. M

Since 25% more money at Poonam

=> Money at Poonam = M + (25% of M)

=> Money at Poonam = M + 0.25M = Rs. 1.25M

Money with Navaneet is thrice the money with Poonam,

=> Money at Navaneet = 3(1.25M) = Rs. 3.75M

Now, sum of all Money = (M + 1.25M + 3.75M) = Rs. 6M

But given the average of the money is Rs. 350

=> 6M/3 = 350

=> 2M = 350

=> M = 350/2 = Rs. 175

=> Amount of money Navaneet has = Rs. 3.75M = 3.75 x 175 = Rs. 656.25.

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8 516
Q:

If the average height of boys in a hall is 180 cm and that of girls is 150 cm. If the average height of the gathering is 165 cm, then find the number of girls present in the hall if the number of boys present in the hall are 78 ?

A) 56 B) 64
C) 87 D) 78
 
Answer & Explanation Answer: D) 78

Explanation:

Using Trial and error method,

we get the number of girls in the hall = 78

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14 912