Which one of the following is correct? 

A and B are two taps which fill a tank individually in 10 minutes and 20 minutes respectively.However,there is a leakage at the bottom,which can empty a filled tank in 40 minutes.If the tank is empty initially,how much time will both taps take to fill the tank with leakage?

If a,b and c satisfy the equation x³-3x²+2x+1=0,then what is the value of 1/a+1/b+1/c

The seven digit number 876p37q is divisible by 225.The values of p and q can be respectively

If (x+1) is the H.C.F of Ax²+Bx+C and Bx²+Ax+C where A≠B,then the value of C is

Consider the following in respect of the equation y=√(x-1)²/(x-1)

1.y=1 if x>1

2.y=-1 if x<1

3.y exists for all values of x

Which of the above statements are correct