Water is flowing at the rate …

Its a rectangualr tank so with the depth, it becomes a cuboid. 

Now, Vollume of a cuboid = lbh = 5000$\times$4400$\times$7 = 154000000 cm³

Pipe is of cylinderical shape, by default, so the water poured by it will fill the tank. That means that should be equal to 154000000 cm³ . So, the volume of the Pipe = $\pi$r²h

Now, r = 7cm & h = ?

Speed of the water = 5Km/h = 5$\times$100000$/$3600 = 1250$/$9 cm/sec

For t seconds, total distance will be 1250t$/$9 cm which will be taken as "h"

So, the Volume of water in the pipe is 22/7 $\times$ 7² $\times$1250t/9 which is equal to 154000000 cm³

So, finally: 154000000 = 22/7 $\times$ 7² $\times$1250t/9

t = (154000000$\times$7$\times$9)$/$ (22$\times$7$\times$7$\times$1250)

t = 7200 sec. = 2 Hrs (Answer)

Height of pipe = 5 km = 500000 cm

Radius of pipe = 7/2 = 3.5 cm

Length of tank = 50 m = 5000 cm

Width of tank = 44 m = 4400 cm

According to question,

Volume of pipe = Volume of tank

πr²h = l x b x h 

22/7(3.5)² x 500000 = 5000 x 4400 x h

h = 7/2 = 3.5 cm

Now,

Time taken to rise water level 3.5 cm = 1 hr

Time taken to rise water level 7 cm = 1/3.5×7 = 2 hours

Lenght of Tank = 50 m = 5000 cm

Width of Tank = 44 m = 4400 cm

Height of Water Level = 7 cm 

Volume of water will be = 5000 * 4400 * 7 = 154000000 cm³

Diameter of Pipe = 14 cm

Radius = 7 cm

Speed of Water = 5km/h = 25/18 m/s

Let time taken to fill tank = t s

then volume of water flow in t s = (pi * 7 * 7 *t*25)/18

Time taken to fill tank = (Volume of Tank ) / (volume of water flow in t Second) =  154000000 / ((pi * 7 * 7 *t*25)/18)