### Query Detail : SSC CGL Tier I

**16 taps are fitted to a water tank. Some of them are water taps to fill the tank and the remaining are outlet taps used to empty the tank. Each water tap fills the tank in 6 hours. Each outlet taps can empty it in 18 hrs. On opening all the taps, the tank is filled in 1.5 hours. Find the number of inlet water taps?
Answer: 7**

Garima,
February 11th 2020,

SSC CGL Tier I

**
**

**Method 1:**

Let no. of inlet tap = x so number of outlet tap = 16 - x

Inlet Outlet

6 18

Lcm = 18 L

eff 3 : -1

So their 1 hr work = 3x + (-1) (16-x) = 18/1.5

3x - 16+x = 12

4x = 28

x = 7

Number of Inlet water taps = 7

**Method 2:**

x(1/6) - (16-x)/(1/18) = 1/1.5

{3x -(16-x)}/18 = 1/1.5

{3x -16 + x)}/18 = 1/1.5

4x - 16 = 12

4x = 28

x = 7

x =5