Twelve men take 6 hours to finish a piece of work. After the 12 men have worked for 1 hour, the contractor decides to call in 8 more men. How many more hours would 20 men take to complete the remaining work?

A) 3

B) 5

C) 2

D) 4

12 men took to 6 hours to complete the work.

It means there is 12 x 6= 72 units of work

Now 12men done work for one hour. So 12 x 1 =12 units of work completed.

Remaining work = 72-12= 60 units

Now the no of men=12+8= 20

So 60 units of work have to complete by 20 men

Therefore 60/20= 3 hours

 

Advertisements

The width of a rectangle is twice the size of its length The length is increased by 30% and width is increased by 20%, what will be the percentage change in the area of rectangle?

A) 4.51

B) 3.87

C) 5.11

D) None of these

Letthe length of rectangle as x and width as y.

y = 2x Area = xy = 2*square of x

Length increased by 30. I presume it is % increase. New X = 1.3x

Width increased by 20%. New Y= 1.2 y = 1.2*2x = 2.4x

Area of the new rectangle = XY = 1.3x * 2.4x = 3.12 * square of x

New rectangle/ old rectangle = 3.12/2.0 = 1.56

New rectangle is 56% bigger than the original rectangle in terms of area.

Advertisements