Quantitative Aptitude - Arithmetic Ability Questions

Here 40% of 80 is given as

40100 x 80 = 8 x 4 = 32

Total repayment amount = $1600 + $368
= $1968
= $82

regular payment= total amount/number of repayments

Let Mohan present age = p

ATQ,

5/6 x p = p - 5

p = 30

His wifes age = 30 - 3 = 27 yrs.

From the given data,

P = 140

But it is given that,

40% of Q + Q = 140 = P

=> Q + [40Q/100] = 140

=> [100Q + 40Q]/100 = 140

=> 140Q = 140 x 100

=> Q = 100

Now,

 3/25 of Q 

= (3/25) x 100

= 3 x 4 

= 12 

Required 3/25 of Q  = 12.

From the given data,

K's profit : L's profit = 7x x 11 : 9x x 7

= 11:9

Therefore, L's profit = 9 x 2460/20 =  Rs. 1107

Almond Selling price = CP(1 + P%/100)

=> CP = 20000, SP = 23000

=> 23000 = 20000 (1 + P/100)

=> P% = 100(23000/20000 - 1) = 15

Then, Olive's P% = 30%

SP for Olive = CP for Sarah = 23000(1 + 30/100) = 29900

Now Sarah wants to earn profit of 8%

=> Sp for Sarah = 29900(1 + 8/100)

= Rs. 32,292.

1. How to find Speed(s) if distance(d) & time(t) is given:

 Speed (S) = Distance (D)Time (T) 

Ex: Find speed if a person travels 4 kms in 2 hrs?

Speed = D/T = 4/2 = 2 kmph.

2.  Similarly, we can find distance (d)  if speed (s) & time (t) is given by

Distance (D) = Speed (S) x Time (T)

Ex : Find distance if a person with a speed of 2 kmph in 2 hrs?

Distance D = S X T = 2 x 2 = 4 kms. 

3.  Similarly, we can find time (t) if speed (s) &  distance (d) is given by

Time (T) = Distance (D)Speed (S)

Ex : Find in what time a person travels 4 kms with a speed of 2 kmph?

Time T = D/S = 4/2 = 2 hrs.

4. How to convert  km/hr into m/sec :

P km/hr = P x 518 m/sec

Ex : Convert 36 kmph into m/sec?

36 kmph = 36 x 5/18 = 10 m/sec 

5. How to convert  m/sec into km/hr :

P m/sec = P x 185 kmph.

Ex : Convert 10 m/sec into km/hr?

10 m/sec = 10 x 18/5 = 36 kmph.

6.  If the ratio of the speeds of A and B is a:b, then the ratio of the times taken by them to cover the same distance is b : a.

7.  Suppose a man covers a certain distance at x km/ hr and an equal distance at y km/hr . Then, the average speed during the whole journey is 2xyx+y km/hr.

In a family with 2 children there are four possibilities:
1) the first child is a boy and the second child is a boy (bb)
2) the first child is a boy and the second child is a girl (bg)
3) the first child is a girl and the second child is a boy (gb)
4) the first child is a girl and the second child is a girl (gg)

But already given that one child is boy. So we have three possibilities of (bb)(bg)(gb).
n(E)= both are boys=BB=1
n(S)= 3
Required probability P = n(E)/n(S) = 1/3.