Quantitative Aptitude - Arithmetic Ability Questions

Q:

There are three boats B1, B2 and B3 working together they carry 60 people in each trip. One day an early morning B1 carried 50 people in few trips alone. When it stopped carrying the passengers B2 and B3 started carrying the people together. It took a total of 10 trips to carry 300 people by B1, B2 and B3. It is known that each day on an average 300 people cross the river using only one of the 3 boats B1, B2 and B3. How many trips it would take to B1, to carry 150 passengers alone?

A) 15 B) 30
C) 25 D) 10
 
Answer & Explanation Answer: A) 15

Explanation:

Combined efficiency of all the three boats = 60 passenger/trip 

 

Now, consider option(a)

 

15 trips and 150 passengers means efficiency  of B1 =  10 passenger/trip 

 

which means in carrying 50 passengers B1 must has taken 5 trips. So the rest trips equal to 5 (10-5 = 5) in which B2 and B3 together carried remaining 250 (300 - 50 = 250) Passengers.

 

Therefore the efficiency of B2 and B3 = 250/5 = 50 passenger/trip  

 

Since, the combined efficiency of B1, B2 and B3 is 60. Which is same as given in the first statement hence option(a) is correct.

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Filed Under: Time and Work

33 12388
Q:

The true discount on a bill due 9 months hence at 16% per annum is Rs. 189. The amount of the bill is

A) 1200 B) 1764
C) 1600 D) 1354
 
Answer & Explanation Answer: B) 1764

Explanation:

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Filed Under: True Discount

13 12368
Q:

A bag contains 7 green and 5 black balls. Three balls are drawn one after the other. The probability of all three balls being green, if the balls drawn are not replaced will be:

A) 123/897 B) 23/67
C) 7/44 D) 12/45
 
Answer & Explanation Answer: C) 7/44

Explanation:

Here, n(E) = 7C1×5C1×5C1

 

And,  n(S) = 12C1*11C1*10C1

P(S) = 7*6*512*11*10 = 7/44

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Filed Under: Probability

13 12354
Q:

A son and father goes for boating in river upstream . After rowing for 1 mile son notices the hat of his father falling in the river. After 5 min he tells his father that his hat has fallen. So they turn round and are able to pick the hat at the point from where they began boating after 5min. Find the speed of river  in miles/hours ?

A) 4 mile/hr B) 6 mile/hr
C) 2 mile/hr D) 5 mile/hr
 
Answer & Explanation Answer: B) 6 mile/hr

Explanation:

Let the speed of river and boat be 'r' m/min and 'b' m/min.
so relative speed in upstream (b-r)m/min and in downstream (b+r)m/min.
Now in upstream distnce covered in 5 min is 5(b-r)miles
so total distnce covered => 1 + 5(b-r)miles in upstream
In downstream distance covered in 5min is 5(b+r)miles
Now 1 + 5(b-r) = 5(b+r)
1+5b-5r = 5b+5r
1 = 10r
r = 1/10 mile/min => 6 mile/hr.

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Filed Under: Time and Distance
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk

15 12352
Q:

A number consists of 3 digits whose sum is 10. The middle digit is equal to the sum of the other two and the number will be increased by 99 if its digits are reversed. The number is :

A) 253 B) 263
C) 273 D) 283
 
Answer & Explanation Answer: A) 253

Explanation:

Let the middle digit be x.

Then, 2x = 10 or x = 5. So, the number is either 253 or 352

Since the number increases on reversing the digits, so the hundred's digit is smaller than the unit's digit.

Hence, required number = 253.

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Filed Under: Problems on Numbers

5 12340
Q:

A man can row 8 kmh in still water. If the river is running at 2 kmh, it takes 4 hrs more upstream than to go downstream for the same distance. Then the distance is given by

A) 54 kms B) 32 kms
C) 45 kms D) 60 kms
 
Answer & Explanation Answer: D) 60 kms

Explanation:

Let the distance be d.

 d8-2-d8+2 = 4

 

=> 2d = 120 

 

=> d = 60 kms.

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Filed Under: Boats and Streams
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23 12323
Q:

Two numbers are respectively 40% and 30% more than a third number. The second number expressed in terms of percentage of the first is ?

A) 92.8% B) 84.23%
C) 87.14% D) 94.1%
 
Answer & Explanation Answer: A) 92.8%

Explanation:

Here, x = 40 and y = 30;
Therefore second number
= [[100+y100+x] x 100 ]% of first number
= [[100+y100+x] x 100 ]% of first number
Second number = 92.8% of the first number.

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Filed Under: Percentage
Exam Prep: GRE , GATE , CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk , Analyst

12 12318
Q:

If 5th March, 2005 is Monday, what was the day of the week on 5th March, 2004 ?

A) Sunday B) Monday
C) Tuesday D) Wednesday
 
Answer & Explanation Answer: A) Sunday

Explanation:

The year 2004 is a leap year. So, it has 2 odd days.

But, Feb 2004 not included because we are calculating from March 2004 to March 2005. So it has 1 odd day only.

The day on 5th March, 2005 will be 1 day beyond the day on 5th March, 2004.

Given that, 5th March, 2005 is Monday.

5th March, 2004 is Sunday (1 day before to 5th March, 2005).

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Filed Under: Calendar
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

26 12312