Quantitative Aptitude - Arithmetic Ability Questions

The probability of an impossible event is 0.

The event is known ahead of time to be not possible, therefore by definition in mathematics, the probability is defined to be 0 which means it can never happen.

The probability of a certain event is 1.

Let 'd' be the distance between A and B
K -time = d/10 + d/9 = 19d/90 hours
L -time = 2d/12 = d/6 hours
We know that, 10 min = 1/6 hours
Thus, time difference between K and L is given as 10 minutes.
=> 19d/90 - d/6 = 1/6
=> (19d-15d)/90 = 1/6
=> 4d/90 = 1/6
Thus,
d= 15/4 km = 3.75 km.

hence the distance between A and B is 3.75 km.

On 31st December, 2005 it was Saturday.

Number of Odd days from the year 2006 to the year 2009 = (1+1+2+1)=5 days.

 On 31st december 2009, It was Thursday

Thus, on 1st Jan, 2010 it is Friday.

The pattern followed is *1 + 1, *2 +2 , *3 + 3 , *4 + 4 , *5 + 5

Let his present earnings be Rs. p

ATQ,

(125/100) x (96/100) x (125/100) x (96/100) x (125/100) x p = 72000

p = Rs. 40,000.

loss = C.P - S.P = 490 - 465.50 =24.50 

loss % = (loss x 100)/C.P = (24.50 x 100)/490 = 5%

The single equivalent payment will be PV + FV.
FV
= Future value of $10,000, 12 months later

$10,000 *(1.0075)/12

$10,938.07
PV=
Present value of $10,000, 24 months earlier

$10,000/(1.0075)24

$8358.31
The equivalent single payment is
$10,938.07 + $8358.31
= $19,296.38

Let no. of boys be 'B' and no. of girls be 'G'

Here from given data,

B + G = 1650 .....(1)

B - G = 400 .....(2)

From (1) & (2), we get

2B = 2050

=> B = 1025

=> G = 1650 - 1025 = 625

Hence, the % of girls = 625 x 100/1650

=> 38% (approx).