Quantitative Aptitude - Arithmetic Ability Questions

Q:

The average age of a group of 10 students is 15 years. When 5 more students join the group, the average age increase by 1 year. The average age of the new students is?

Answer

Total age of 10 students = 150 years


Total age of 15 students = 240 years


Total age of 5 new students = 240 - 150 = 90 years


\inline \therefore Average age of 5 new students =  = 18 years

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Subject: Problems on Ages

153 30468
Q:

The smallest number which when diminished by 7,  is divisible by  12, 16, 18, 21 and 28 is

A) 1008 B) 1015
C) 1022 D) 1032
 
Answer & Explanation Answer: B) 1015

Explanation:

Required Number = (L.C.M  of 12, 16, 18,21,28)+7

= 1008 + 7

= 1015

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Filed Under: HCF and LCM

101 30467
Q:

In a scheme, a pack of three soaps with MRP Rs.45 is available for Rs.42. If it still gives a profit of 5% to the shopkeeper, then the cost price of the pack is ?

A) 38 B) 39
C) 40 D) 41
 
Answer & Explanation Answer: C) 40

Explanation:

Given M.P=45,S.P=42, Profit = 0.05

Let C.P=x , Then

Profit = (42-x)/x = 0.05
=> x = 40.

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Filed Under: Profit and Loss
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
Job Role: Bank Clerk , Bank PO

57 30386
Q:

x = y - (50/y), where x and y are both > 0 

If the value of y is doubled in the equation above, the value of x will

A) decrease B) stay the same
C) increase four fold D) increase to more than double
 
Answer & Explanation Answer: D) increase to more than double

Explanation:

The best approach is to pick a number that satisfies the rules that x and y are greater than 0. So for example you could choose 25 for y.

The value of x before doubling is then 25 - 50/25 = 23

The value after doubling y will be 50 - 50/50 = 49, which is more than double.

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Filed Under: Numbers
Exam Prep: GRE

5 30385
Q:

A boat takes 19 hours for travelling downstream from point A to point B and coming back to a point C which is at midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B ? 

A) 180 km B) 160 km
C) 140 km D) 120 km
 
Answer & Explanation Answer: A) 180 km

Explanation:

Speed in downstream = (14 + 4) km/hr = 18 km/hr;

Speed in upstream = (14 – 4) km/hr = 10 km/hr.

Let the distance between A and B be x km. Then,

x/18 + (x/2)/10 = 19 ⇔ x/18 + x/20 = 19 ⇒ x = 180 km.

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Filed Under: Boats and Streams
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

90 30339
Q:

In a regular week, there are 5 working days and for each day, the working hours are 8. A man gets Rs. 2.40 per hour for regular work and Rs. 3.20 per hours for overtime. If he earns Rs. 432 in 4 weeks, then how many hours does he work for ?

A) 160 B) 175
C) 180 D) 195
 
Answer & Explanation Answer: B) 175

Explanation:

Suppose the man works overtime for x hours.

Now, working hours in 4 weeks = (5 x 8 x 4) = 160.

Therefore,  160 * 2.40 + x * 3.20 = 432

 => 3.20x = 432 - 384 = 48

 => x = 15.

 Hence, total hours of work = (160 + 15) = 175.

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Filed Under: Simplification

34 30309
Q:

A dog takes 3 leaps for every 5 leaps of a hare. If one leap of the dog is equal to 3 leaps of the hare, the ratio of the speed of the dog to that of the hare is :

A) 9:5 B) 2:3
C) 4:7 D) 5:6
 
Answer & Explanation Answer: A) 9:5

Explanation:

Dog : Hare = (3*3) leaps of hare : 5 leaps of hare = 9 : 5.

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Filed Under: Ratios and Proportions

115 30270
Q:

Three circles of radius 3.5cm are placed in such a way that each circle touches the other two. The area of the portion enclosed by the circles is

A) 1.967 B) 1.867
C) 1.767 D) 1.567
 
Answer & Explanation Answer: A) 1.967

Explanation:

required area = (area of an equilateral triangle of side 7 cm)- (3 * area of sector with à = 60 degrees and r = 3.5cm)
34*7*7-3*227*3.5*3.5*60360 sq cm

 

=34*49-11*0.5*3.5 sq cm

 

= 1.967 sq cm

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

34 30254