Exams

A takes 24 days to complete a work.
B is 20% more efficient than A,
hence B will take (24*100)/120 = 20 days.
C takes (20+10) = 30 days.
Time taken by A & C in completing the work = (24*30)/(24+30) = (24*30)/54 = 40/3 days.

            => log60(3*4*5)

                              =>     log6060

                                   = 1

Hence, the missing number iss 25.

From the given data,

The part of honey in the first mixture = 1/4

The part of honey in the second mixture = 3/4

Let the part of honey in the third mixture = x

Then,

1/4             3/4

           x

(3/4)-x     x-(1/4) 

Given from mixtures 1 & 2 the ratio of mixture taken out is 2 : 3

=> 34-xx-14=23

=> Solving we get the part of honey in the third mixture as 11/20

=> the remaining part of the mixture is water = 9/20

Hence, the ratio of the mixture of honey and water in the third mixture is 11 : 9 .

Given, y/(x - z) = (y + x)/z = x/y
yz = xy + x2 - yz - xz ....(1)
Also xy = yx-z ⇒x2 -xz = y2 ....(2)
Using (1) and (2), we get yz = xy - yz + y2
2yz = xy + y2
2z = x + y
Only option (B) satisfies the equation.