Quantitative Aptitude - Arithmetic Ability Questions

Q:

The ratio of the speed of Two trains is 5:8. Sum of their length is 660. The ratio of time taken to cross an Electric Pole by train A and B is 4:3. What is the difference between the length of two trains?

A) 50m B) 40m
C) 60m D) 45m
 
Answer & Explanation Answer: C) 60m

Explanation:

Ans.
Given that length of first train + length of second train = 660
Speed of first train : Speed of second train = 5:8 =5x : 8x
Time taken to cross the poll by two trains = 4:3 =4y:3y
Now ,
(5x*4y) + (8x*3y) = 660
44xy = 660
xy = 15
L1 - L2 = 24xy -20xy = 4xy = 60 m

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Filed Under: Problems on Trains
Exam Prep: AIEEE , Bank Exams , GATE

2 4332
Q:

The average marks of 50 students in an examination was 65. It was later found that the marks of one student had been wrongly entered as 83 instead of 38. The correct average is?

A) 63.9 B) 64.5
C) 64.7 D) 64.1
 
Answer & Explanation Answer: D) 64.1

Explanation:
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Filed Under: Average
Exam Prep: Bank Exams

1 4330
Q:

Find the present worth of a bill of Rs.28000 due 2 years at 12% compound interest. Also find the true discount.

A) 300 B) 350
C) 250 D) 275
 
Answer & Explanation Answer: A) 300

Explanation:

PW = Amount1+R100T=28001+121002   = Rs.2500 

 

TD = Amount - PW = 2800 - 2500 = Rs.300

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Filed Under: True Discount

0 4327
Q:

Walking at a speed of 10 km/hr, Madhu reaches her university 15 minutes late. Next time she increases her speed by 2 km/hr, but she is still late by 5 minutes. The distance of the university from her house is:

A) 15 km B) 30 km
C) 20 km D) 10 km
 
Answer & Explanation Answer: D) 10 km

Explanation:
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Filed Under: Time and Distance
Exam Prep: AIEEE , Bank Exams , CAT , GATE

12 4322
Q:

Using numbers from 0 to 9 the number of 5 digit telephone numbers that can be formed is

A) 1,00,000 B) 59,049
C) 3439 D) 6561
 
Answer & Explanation Answer: C) 3439

Explanation:

The numbers 0,1,2,3,4,5,6,7,8,9 are 10 in number while preparing telephone numbers any number can be used any number of times.

 

This can be done in 105ways, but '0' is there

 

So, the numbers starting with '0' are to be excluded is 94 numbers.

 

 Total 5 digit telephone numbers = 105- 94 = 3439

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Filed Under: Permutations and Combinations
Exam Prep: AIEEE , Bank Exams , CAT , GATE
Job Role: Bank Clerk , Bank PO

5 4313
Q:

There is a 3 digited number. 3rd digit is the square root of the 1st digit. 2nd digit is the sum of 1st and 3rd. And that number is divisible by 2,3,6,7. What is that number?

A) 121 B) 943
C) 462 D) None
 
Answer & Explanation Answer: C) 462

Explanation:

Assume that the number is taken as XYZ.
Condition 1 => Z = sq.root(x) => Possible digits of X is 1,4,9
Condition 2 => Y = X + Z
X Y Z
1 2 1
4 6 2
9 12 3 => (wrong because it is 4 digit.)

and 121 is not divisible by 2

The answer is 462.

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Filed Under: Numbers
Exam Prep: Bank Exams , CAT , GATE
Job Role: Bank Clerk , Bank PO

3 4313
Q:

Consider a regular hexagon ABCDEF. Two towers are situated at B and C. The angle of elevation from A to the top of the tower at B is 30 deg, and the angle of elevation to the top of the tower at C is 45 deg. What is the ratio of the height of towers at B and C?

A) 1:√3 B) 1:3
C) 1:2 D) 1:2√3
 
Answer & Explanation Answer: B) 1:3

Explanation:

Let the side of regular hexagon be ‘a’

Let height of the tower 1 be h1 and tower 2 be h2

Height of tower 1 = h1 = (distance between A and B)* (tan 30o)= a.1/√3

Distance between A and C = 2*√3.a/2= √3a

Height of tower 2 = h2 = (distance between A and C)* (tan 45o) = √3a.1 = √3a

Ratio of height of towers at B and C respectively =a/√3/√3a = 1/3.

 

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Filed Under: Simplification
Exam Prep: Bank Exams

3 4312
Q:

A research team of 6 people is to be formed from 10 chemists,5 politicians, 8 economists and 15 biologists.How many teams have atleast 5 chemists?

A) 7350 B) 6400
C) 6379 D) 7266
 
Answer & Explanation Answer: D) 7266

Explanation:

10C5 x 28C1 x 10C6 = 7266

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