Let the heights of the cylinder and cone be h and H respectively.
∵ πr²h = πr²H / 3

Correct Option: D

Let the heights of the cylinder and cone be h and H respectively.
∵ πr²h = πr²H / 3
⇒ h/H = 1/3
∴ h : H = 1 : 3.
So their heights are in the ratio 1 : 3.

Of every 4 employees, 1 is college graduate and 3 are not college graduates.

Correct Option: C

Of every 4 employees, 1 is college graduate and 3 are not college graduates.
∴ The required ration = 1 : 3

The number of students talking English = 4/(4 + 3) x 840

Correct Option: A

The number of students talking English = 4/(4 + 3) x 840 = 480

Let the number of 25 paise, 10 paise and 5 paise coins be N, 2N and 3N, respectively. Then ,
N + 2N + 3N = 60

Correct Option: C

Let the number of 25 paise, 10 paise and 5 paise coins be N, 2N and 3N, respectively. Then ,
N + 2N + 3N = 60
⇒ N = 10
∴ The number of 5 paise coins = 3 x 10 = 30

Let 5A = 12B = 6C = k
Then, A = k/5, B = k/12 and C = k/6

Correct Option: B

Let 5A = 12B = 6C = k
Then, A = k/5, B = k/12 and C = k/6
∴ A : B : C = k/5 : k/12 : k/6 = 12 : 5 : 10