Quantitative Aptitude - Arithmetic Ability Questions

Let the required number of days be x.

Less cows, More days (Indirect Proportion)

Less bags, Less days (Direct Proportion)

$$\begin{gathered} cows 1:40 :40:x \\ bags 40:1 :40:x \\ \end{gathered}$$

1 x 40 x x = 40 x 1 x 40

=>  x = 40.

(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.

Arun has completed 13rd of the work in 8 days

Then he can complete the total work in

13 ---- 8

 1 ---- ?

= 24 days

But given Akhil is only 60% as efficient as Arun

Akhil =124×60100=140

Akhil can complete the total work in 40 days

Now, remaining 2/3rd of work can be completed in

 1  ------   40

23 ------   ?  

= 26.66 days.

To get the solution that contains 1 part of milk and two parts of water,
they must be mixed in the ratio as
7x+6x/5y+11y = 1/2
26x = 16y
x/y = 16/26
x/y = 8/13

Given a2 + b2 = c2

Now  1logc+ab + 1logc-ab

= logbc+a + logbc-a

= logbc2-a2

= 2logbb = 2

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.

Let x = the youngest child. Each of the other four children will then be x+3, x+6, x+9, x+12. 

We know that the sum of their ages is 50 .

so, x+(x+3)+(x+6)+(x+9)+(x+12) = 50

=>  x= 4

 The youngest child is 4 years old.