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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 & Explanation 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

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Filed Under: Average

Q:

123 typists typeed 984 papers in 1/15 hour. The number of papers typed for minute by a average typist is:

A) 1	B) 2
C) 3	D) 5

Answer & Explanation Answer: B) 2

Explanation:

Use unitary method:

In $\inline \frac{1}{15}$ hours, 123 typists can type 984 paper

In 1 minute, 123 typists can type $\inline \frac{984}{4}$ = 246 papers

In 1 minute, 1 typist can type $\inline \frac{246}{123}$ =2 papers [ Hint $\inline \frac{1}{15}$ hours = 4 minutes]

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Q:

There are two containers, the first one contains 1 litre pure water and the second one contains 1 litre pure milk.Now 5 cups of water from the first container is taken out is mixed well in the second container. Then, 5 cups of this mixture is taken out and is mixed in the first container. Let A denote the proportion of milk in the first container and B denote the proportion of water in the second container then:

A) A	B) A=B
C) A>B	D) can't be determined

Answer & Explanation Answer: B) A=B

Explanation:

Here the ratio of mixtures( i.e milk , water) doesnot matter. But the important point is that whether the total amount ( either pure or mixture ) being transferred is equal or not.Since the total amount ( i.e 5 cups) being transferred from each one to another , hence A =B.

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Filed Under: Ratios and Proportions

Q:

Alloy A contains 40% gold and 60% silver. Alloy B contains 35% gold and 40% silver and 25% copper. Alloys A and B are mixed in the ratio of 1:4 .What is the ratio of gold and silver in the newly formed alloy is?

A) 20% and 30%	B) 36% and 44%
C) 25% and 35%	D) 49% and 36%

Answer & Explanation Answer: B) 36% and 44%

Explanation:

Assume the weight of alloy a is 100 kg

Therefore, The weight of alloy B is 400kg

Gold silver copper

A 40kg 60kg 0kg

B 140kg 160kg 100kg

total 180kg 220kg 100kg

Therefore, Ratio of gold and silver in new alloy = $\frac{180}{500} : \frac{200}{500}$ = 36% :44%

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Filed Under: Ratios and Proportions

Q:

The number of oranges in three baskets are in the ratio of 3 : 4 : 5. In which ratio the no. of oranges in first two baskets must be increased so that the new ratio becomes 5 : 4 : 3?

A) 1:3	B) 2:1
C) 3:4	D) 2:3

Answer & Explanation Answer: B) 2:1

Explanation:

Let, B1 : B2 : B3 = 3x : 4x : 5x

again B1 : B2 : B3 = 5y : 4y : 3y

Since there is increase in no.of oranges in first two baskets only, it means the no. of oranges remains constant in the third basket

Therefore, 5x = 3y

Hence 3x : 4x : 5x => $\frac{9 y}{5} : \frac{12 y}{5} : \frac{15 y}{5}$ = 9y:12y:15y

and 5y : 4y : 3y => 25x : 20x : 15x

Therfore, increment in first basket = 16

Increment in second basket = 8

Thus, required ratio = 16/8 = 2:1

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Filed Under: Ratios and Proportions

Q:

In Maa Yatri Temple every devotee offers fruits to the orphans. Thus every orphan receives bananas, oranges and grapes in the ratio of 3:2:7 in terms of dozens. But the weight of a grape is 24 gm and weight of a banana and an orange are in the ratio of 4:5, while the weight of an orangeis 150gm. Find the ratio of all the three fruits in terms of weight, that an orphan gets

A) 90:75:42	B) 180:150:82
C) 75:42:90	D) None of these

Answer & Explanation Answer: D) None of these

Explanation:

Ratio of fruits (by dozen) = 3:2:7

Ratio of fruits (by weight) = 120 :150: 24

Therefore, Ratio of fruits (combined) by weight = 3 x 120 : 2 x 150 : 7 x 24 = 30 : 25 : 14

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Filed Under: Ratios and Proportions

Q:

Pooja, Shipra and Mounika are three sisters .Pooja and Shipra are twins. The ratio of sum of the ages of Pooja and Shipra is same as that of Mounika alone. Three years earlier the ratio of age of Pooja and Mounika was 2:7 . what will be the age of Shipra 3 years hence?

A) 21 years	B) 16 years
C) 8 years	D) 12 years

Answer & Explanation Answer: C) 8 years

Explanation:

Since Pooja and Shipra are twins so their ages be same. Let their ages be x and age of Mounika be y , then

x+x = y -------(1)

and $\frac{x - 3}{y - 3} = \frac{2}{7} \Rightarrow 7 x - 2 y = 15$

Now, from equation (1),

7x - 4x = 15 => x = 5

So the age of Shipra 3 years hence will be 5+3 = 8 years

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Filed Under: Ratios and Proportions

Q:

At a casino in mumbai, there are three tables A, B and C. The payoffs at A is 10:1, at B is 20:1 and at C is 30:1. If a man bets Rs 200 at each table and win at two of the tables, what is the maximum and minimum difference between his earnings can be?

A) Rs.2500	B) Rs.2000
C) Rs.4000	D) None of these

Answer & Explanation Answer: C) Rs.4000

Explanation:

Maximum earning will be only when he will won on the maximum yielding table.

A ----> 10:1

B ----> 20:1

C ----> 30:1

i.e, he won on B and C but lost on A

20 x 200 + 30 x 200 -1 x 200 = 9800

minimum earning will be when he won on table A and B and lose on that table 3.

Therefore, 10 x 200 + 20 x 200 - 1 x 200 = 6000-200 = 5800

Therefore, Difference= 9800 - 5800 = 4000

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Filed Under: Ratios and Proportions

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