Quantitative Aptitude - Arithmetic Ability Questions

Let the number of boys = b

Let the number of girls = g

From the given data,

81b + 83g = 81.8(b + g)

81.8b - 81b = 83g - 81.8g

0.8b = 1.2g

b/g = 1.2/0.8 = 12/8 = 3/2

=> g : b = 2 : 3

Hence, ratio between the number of girls to the number of boys = 2 : 3.

We know that, Total probability = 1

Given probability of black stones = 1/4

=> Probability of blue and white stones = 1 - 1/4 = 3/4

But, given blue + white stones =  9 + 6 = 15

Hence,

3/4 ----- 15

 1   -----  ?

=> 15 x 4/3 = 20.

Hence, total number of stones in the box = 20.

Quarter of Kg means 250 gm

Less weight, less price (Direct Proportion)

So,

250 : 200 :: 60 : x => x = 48

So 200 gm will cost 48 paise.

The given 3b - 7 < 32 can be solved as

3b - 7 < 32

3b < 39

b < 13.

Let original length = x and original breadth = y.

Original area = xy.

New length = x/2 and New breadth = 3y.

New area = (x/2 * 3y) = (3/2 )xy

Therefore,  Increase % = [(1/2)xy * (1/xy) * 100] % = 50%

A=P(1+r)^t

G.C.D is nothing but H.C.F

Given numbers are 1.08 , 0.36 and 0.90

we can take as 108, 36 and 90 

Then required H.C.F is 18.

Therefore, H.C.F of given numbers is 0.18.

Count the number of odd days from the year 2007 onwards to get the sum equal to 0 odd day.

Year : 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017
Odd day : 1 2 1 1 1 2 1 1 1 2 1

Sum = 14 odd days => 0 odd days.
Calendar for the year 2018 will be the same as for the year 2007.