Quantitative Aptitude - Arithmetic Ability Questions

Q:

If a box contains 10 bulbs,of which just three are defective. If a random sample of five bulbs is drawn, find the probability that the sample contains no defective bulbs.

A) 5/12 B) 7/12
C) 3/14 D) 1/12
 
Answer & Explanation Answer: D) 1/12

Explanation:

Total number of elementary events = 10C5

 

Number of ways of selecting no defective bulbs i.e., 5 non-defective bulbs out of 7 is 7C5.

 

So,required probability =7C510C5 = 1/12.

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Filed Under: Probability

20 13155
Q:

A can write 32 pages in 6 hours and B can write 40 pages in 5 hours. If they write together, in how many hours they can write 110 pages ?

A) 7 hrs B) 6 hrs 10 min
C) 5 hrs 25min D) 8 hrs 15 min
 
Answer & Explanation Answer: D) 8 hrs 15 min

Explanation:

A can write in 1hour = 32/6 pages

Similarly, B in 1 hour = 40/5 pages

Together (A+B) in 1 hour = 32/6 + 40/5 = 40/3

So, A+B write 40/3 pages in 1 hour

A+B write 110 pages in (3/40) x 110 Hours = 8 hours 15 min.

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

8 13154
Q:

The highest score in an inning was  3/11 of the total and the next highest was 3/11 of the reminder . If the score  differ by 9, the total score was :

A) 110 B) 121
C) 132 D) 143
 
Answer & Explanation Answer: B) 121

Explanation:

Let the score be x. Then the highest score = 3x/11.

Reminder = (x - 3x/11) = 8x/11 .Next the highest score = 3/11 of 8x/11 = 24x/121.

3x/11 - 24x/11 = 9 <=> 33x - 24x = 9*121 <=> x= 121..

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Filed Under: Simplification

17 13147
Q:

If the true discount on s sum due 2 years hence at 14% per annum be Rs. 168, the sum due is ?

A) Rs.948 B) Rs.876
C) Rs.768 D) Rs.658
 
Answer & Explanation Answer: C) Rs.768

Explanation:

P.W. = 100×T.DR×T = 100×16814×2 = 600.

Sum = (P.W. + T.D.) = Rs. (600 + 168) = Rs. 768.

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

17 13145
Q:

The effective annual rate of interest corresponding to a nominal rate of 6% per annum payable half-yearly is

A) 6.06% B) 6.07%
C) 6.08% D) 6.09%
 
Answer & Explanation Answer: D) 6.09%

Explanation:

Amount of Rs. 100 for 1 year

when compounded half-yearly = Rs.[100*(1+3/100)^2]=Rs.106.09

Effective rate=(106.09-100)%=6.09%

 

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Filed Under: Compound Interest
Exam Prep: Bank Exams
Job Role: Bank PO

10 13136
Q:

A train covers a distance in 50 minutes, if it runs at a speed of 48kmph on an average. Find the speed at which the train must run to reduce the time of journey to 40 minutes.

A) 50 km/hr B) 60 km/hr
C) 65 km/hr D) 70 km/hr
 
Answer & Explanation Answer: B) 60 km/hr

Explanation:

We are having time and speed given, so first we will calculate the distance. Then we can get new speed for given time and distance.
Lets solve it.

Time = 50/60 hr = 5/6 hr
Speed = 48 mph
Distance = S*T = 48 * 5/6 = 40 km

New time will be 40 minutes so,
Time = 40/60 hr = 2/3 hr
Now we know,
Speed = Distance/Time
New speed = 40*3/2 kmph = 60kmph

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Filed Under: Time and Distance
Exam Prep: GRE

26 13131
Q:

How many iron rods, each of length 7 mts and diameter 2 cms can be made out of 0.88 cubic metre of iron ?

A) 500 B) 600
C) 400 D) 300
 
Answer & Explanation Answer: C) 400

Explanation:

Given length of iron rod =7 mts and  and diameter of rod = 2 cms 

=> r = 1/100 mts

Therefore,  Volume of one rod = πr2h cu. m =  227×11002×7cu. m = 115000 cu. m

Given volume of iron = 0.88 cu. m 

Therefore, Number of rods = 0.88×500011 = 400.

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Filed Under: Volume and Surface Area
Exam Prep: CAT
Job Role: Bank PO

17 13122
Q:

If 3x+7=x2+p=7x+5, what is the value of P ?

A) 17/2 B) 25/3
C) 33/4 D) 41/5
 
Answer & Explanation Answer: A) 17/2

Explanation:

 

 

3x+7=7x+5=>7x-3x=2=>4x=2=>x=2

 

Now, 3x+7=x2+p=32+7=14+p=>p=172

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Filed Under: Simplification

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