CAT Questions

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One grandfather, One father and One son makes two fathers and two sons.

Let the 1 day work of a boy=b and a girl=g, then
2b + g = 1/5 ---(i) and
b + 2g = 1/6 ---(ii)
On solving (i) & (ii), b=7/90, g=2/45
As payment of work will be in proportion to capacity of work and a boy is paid $ 28/week,
so a girl will be paid 28×245790 = 16 $.

The third proportional of two numbers p and q is defined to be that number r such that

p : q = q : r.

Here, required third proportional of 10 & 20, and let it be 'a'

=> 10 : 20 = 20 : a

10a = 20 x 20

=> a = 40

Hence, third proportional of 10 & 20 is 40.

Let the speeds of the two trains be x m/sec and y m/sec respectively.

Then, length of the first train = 27 x meters, and

length of the second train = 17 y meters.

(27 x + 17 y) / (x + y) = 23

=> 27 x + 17 y = 23 x + 23 y

=> 4 x = 6 y

=> x/y = 3/2.

Given S = 17 yrs

A = 16 yrs

B = 12 yrs

Average = 17 + 16 + 12/3 = 15 yrs

Given if Aslam added to them, their average increases by 5

=> Average of 4 members = 20

Let the age of Aslam be 'x'

Then, 

17 + 16 + 12 + x /4 = 20

=> x = 80 - 45

=> x = 35. 

Hence, the age of Aslam is 35 yrs.

One-quarter of one-seventh = 1/4 x 1/7
= 1/28
Now, 1/28 of a land costs = Rs. 30,000
Thus, 8/35 of the land will cost = 30,000 x 28 x 4/15
= Rs. 2,24,000.

Given a2 + b2 = c2

Now  1logc+ab + 1logc-ab

= logbc+a + logbc-a

= logbc2-a2

= 2logbb = 2

(16M + 12W) x 20 = 18W x 40

=> 2M = 3W

Then,
Convert all men into women

12M + 27W = 27 + 12 x 3/2W = 45W

Let number of days required be 'D'

=> 18 x 40 = 45 x D

=> D = 16 days.