Kalpesh Sharma

***. 15 men take 21 days of 8 hrs. Each does a piece of work. How many days of 6 hrs each would it take for 21 women if 3 women do as much work as 2 men?

Ans. 30

Ex. One hour’s work = 1/(15*21*8)
Assume X days requires for women to do work.
One hour’s work = 1/(21*X*6)
Comparing one hour’s work, we get X=20 days.
But 2 men work = 3 women work so X = (20*3)/2 = 30

***. If on an item a company gives 25% discount, they earn 25% profit. If they now give 10% discount then what is the profit percentage.

Ans. 50%

***. Three pipes, A, B, & C are attached to a tank. A & B can fill it in 20 & 30 minutes respectively while C can empty it in 15 minutes. If A, B & C are kept open successively for 1 minute each, how soon will the tank be filled?

Ans. 167 minutes. Ex. In 3 minutes it fills 0.017 so in 165 minutes it fills 0.935 and then in 2 minutes A and B fills 0.05+0.033, so it full.

***. There are two circles, one circle is inscribed and another circle is circumscribed over a square. What is the ratio of area of inner to outer circle?

Ans. 1:2
Ex. area of inner circle = PI*r*r
Area of outer circle = PI*a*a where a=root(2)*r

***. A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to complete the work if both work together?

Ans. 22½days

Ex. Let, B takes X days to do a work. So A takes X-60 days.
Now A works thrice, so 3(X-60) = X. By solving we get X=90

A works in 1 day = 1/30
B works in 1 day = 1/90
If they work combine, work done in 1 day = 1/30+1/90 = 4/90
So, the work will be completed in 90/4 days.