Quantitative Aptitude - Arithmetic Ability Questions

Let the age of A = A, B = B and C = C

From given

A = 3B

4 years ago,

C-4 = 2(A-4);

After 4 years

A + 4 = 31;

A = 27;
sub in above B, we get B = 9
C = 2(27 - 4) + 4 = 46 + 4 = 50

Hence B = 9yrs and C = 50yrs.

Four tenths = 0.4

Five thousandths = 0.005

The average is (0.4 + 0.005)/2 = 0.2025

Let the present age of person be   x years.

Then, 3(x + 3) - 3(x - 3 ) = x   <=> (3x + 9) - (3x - 9) = x  <=> x = 18..

capacity of a tank = volume of tank 

= [ (8 x 100) x (6 x 100) x (2.5 x 100) ]/ 1000 litres 

= 120000 litres

The day of the week repeats every 7 days.

Given today is Friday. Again Friday is repeated on the 7th day, 14th,... on 7 multiple days.

Hence, Friday is on the 63rd day, as 63 is multiple of 7.

Now, the required day of the week on the 65th day is Sunday.

Ratio of the speeds of A and B =5 : 1 = 5 :3

Thus, in race of 5 m, A gains 2 m over B.

2 m are gained by A in a race of 5 m.

80 m will be gained by A in race of 52*80 m =200m

=> Winning post is 200 m away from the starting point.

C.I.= Rs.[4000*(1+10/100)^2-4000]

 =Rs.840

sum=Rs.(420 * 100)/3*8=Rs.1750