Exams

required area = [14 x 14 - (4 x 1/4 x 22/7 x 7 x 7) ]sq.cm

= 196 - 154 = 42 sq.cm.

Let Ben’s age now be B

Anita’s age now is A.

(A - 6) = P(B - 6)

But A is 17 and therefore 11 = P(B - 6)

11/P = B-6

(11/P) + 6 = B

Let Kumar’s present age be "x" years and Sailesh’s present age be "y" years.
Then, according to the first condition,

x - 10 = 3(y - 10) => x - 3y = - 20 ........(1)

Now, Kumar’s age after 10 years = (x + 10) years.

Sailesh’s age after 10 years = (y + 10) years.

(x + 10) = 2 (y + 10)  => x - 2y = 10 ......(2)

Solving (1) and (2),

we get x = 70 and y = 30

Kumar’s present age = 70 years    and  Sailesh’s present age = 30 years.

It is given that efficiency ratio =3:1

so time ratio will be 1:3 (since work is same)

Also given that time diff = 32 days. ratio difference = 3-1 =2 

2 ratio = 32 days

1 ratio = 16 days.

So A will alone finish it in 16 days and B will finish it in 16*3 = 48 days.

Total work = LCM of 16 and 48 = 48.

Total time = Total work/Total efficiency 

ie; 48/4= 12 days.