Quantitative Aptitude - Arithmetic Ability Questions

Let required fraction be  then 

           ............. (i)

and          ............ (ii)

Solving (i) and (ii) we get x=3, y=5

 Required fraction = 

Suppose A, B and C take x, x/2 and x/3 respectively to finish the work.
Then, (1/x + 2/x + 3/x) = 1/2
6/x = 1/2 => x = 12
So, B takes 6 hours to finish the work.

Given 5:6 :: 7:10 :: 6:5

We know that compound ratio is calculated as
a:b :: c:d :: e:f
(axcxe):(bxdxf)

=> (5x7x6):(6x10x5)
=> (210):(300)
= 7:10

For 30 days he receives

30 x 25 = 750
               

Actually he gets 425

Therefore, Fine is 750 - 425 =  325

=> No of days absent = 325/(25+7.50)= 10

Given 30% of 500

$$\begin{gathered} = 30100 x 500 \\ = 30 x 5 \\ = 150 \end{gathered}$$

Hence, 30% of Rs. 500 = Rs. 150.

Given, 

25% of three-seventh of 26% of a number is 145.5

Let the required number be 'N'

i.e, 25100x37x26100xN = 145.5

N = 145.5x7x1000075x26

=> N = 5223.07

Let the speed of current = 'C' km/hr

Given the speed of boat in still water = 6 kmph

Let 'd' kms be the distance it covers.

According to the given data,

Boat takes thrice as much time in going the same distance against the current than going with the current

i.e, d8 - C = 3 × d8 + C

$$\begin{gathered} ⇒ 24 - 3C = 8 + C \\ ⇒ 4C = 16 \\ ⇒ C = 4 kmph \end{gathered}$$

Hence, the speed of the current C = 4 kmph.