One tap fill a tank in 20 minute and another tap fill it in 12 minute . the tank being empty and if both tap are opened together in how many minutes the tank will be full?

15/2 or 7.5 minutes

Step-by-step explanation:

Tap 1 fill a part of tank in 1 minute = 1/20

Tap 2 fill a part of tank in 1 minute = 1/12

2 tap of tank fill in 1 minute = 1/12 + 1/20

= 2/ 15

So if both tap open, the tank will be filled in 1/(2/15) = 15/2 or 7.5 mins

Hope this help :3

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.

11) obtuse

13)right

15) acute