Answer:
here's the answer I have in the photo and solution too
I'm not 100% sur what it is asking but I think the expression would be
15 min. * 10 = min. till the tank is full
To find the angle of vertex E,we need to first find the sum of interior polygons to determine x:

In this case,the equation would be:
(7-2)×180°
=5×180°
=900°
We can then find the value of x:
(4)6x+(2)2x+8x=900°
24x+4x+8x=900°
36x=900°
x=25°
The interior angle of vertex E:
6x=6(25)=150°
Therefore,the interior angle of vertex E is 150°.
Hope it helps!