Answer:
1.8m
Explanation:
Let the Elastics of the steel ASTM-36 
The strain of the bar when subjected to 150 MPa is

Therefore, if the bar elongates by 1.35 mm, then the original length L would be:

or 1.8m
Subtract the total mass of the tank and water by the mass of the empty tank. That will yield the mass of the water.
51.8 - 3.64 = 48.16.
Your answer is 48.16 kg
If your talking about the chemical equations like combustion, single displacement, etc. Then the equation would be double displacement:
AB + CD ---> AD + CB
The horizontal speed has no effect on how long it takes to reach the ground.
A bullet shot from a gun and a bullet dropped from the front end of the gun
at the same time as the shot both hit the ground at the same time.
The number that counts is the height from which it fell . . . the 1.25 m.
I'll use this very useful formula:
Distance of free fall,
starting from rest = (1/2) · (gravity) · (time)²
1.25 m = (1/2) · (9.8 m/s²) · (time)²
Divide each side
by 4.9 m/s² : 1.25 m / 4.9 m/s² = time²
0.2551 sec² = time²
Square root each side: 0.505 sec = time
It looks like the correct choice is approximately 'A'. (rounded)