Quantitative Aptitude - Arithmetic Ability Questions

Speed = 108 km/hr
enter a tunnel,, means that the train covers a distance equal to its own length
so (108 x 5/18) = x/4 where x= length of train
hence x = 120 mtrs
to pass completely train has to travel a distance = (x + tunnel length) that is 1120 mtrs.
so (1120/t) = (108x5/18)
t = 37.33 sec

Let the present ages be K,M

Given K/M = 4/5

5K - 4M = 0 ......(1)

Also given that,

M - (K + 5) = 3

M - K = 8 .........(2)

Then, by solving (1) & (2)

M = 40 yrs and K = 32 yrs

Hence, Total of ages = 40 + 32 = 72 yrs

Difference of ages = 40 - 32 = 8 yrs.

We have: (l - b) = 23 and 2(l + b) = 206 or (l + b) = 103. 

Solving the two equations, we get: l = 63 and b = 40. 

Area = (l x b) = (63 x 40) sq.m

= 2520 sq.m

Let 'B' be the nuber of bricks.

=> 10 x 4/100 x 5 x 90/100 = 25/100 x 15/100 x 8/100 x B

=> 10 x 20 x 90 = 15 x 2 x B

=> B = 6000

S = { 1, 2, 3, 4, 5, 6 } 

=> n(S) = 6

E = { 3, 6}

=> n(E) = 2

Therefore, P(E) = 2/6 =1/3

Average speed=total distance/total time
Let distance to store be  K
then, total time =(K/20)+(K/30)=K/12
and, total time =(2K)
so average speed= 2K / (K/12) = 24kmph.

Let the sum invested be Rs. P

Let the rate of interest be R% per annum

=> Interest earned for 5 years = (P x 5 x R/100) = PR/20

Now, given that the interest earned increased by Rs. 600 if the Rate increased to (R+2)%

=> SI = (P x 5 x (R+2))/100 = PR/20 + 10P/100

Hence,

PR/20 + 10P/100 = PR/20 + 600

=> P = 6000

Therefore, the sum invested is Rs. 6000