Quantitative Aptitude - Arithmetic Ability Questions

If x = a + 1a, y = a - 1a ,(a>0), then the value of x4+y4-2x2y2 is

Reflection of the point (­1,4) in the x­axis is

If √(1 + cot2A) = x, then the value of x is

Find the unit place digit in 192102 + 193103

If a = 5, b = 4, c = 8 then find the value of (a3 + b3 + c3 - 3abc)/(ab + bc + ca - a2 - b2 - c2)

If x2 + ax + b, when divided by x + 3, leaves a remainder of -1 and x2 + bx + a, when divided by x - 3, leaves a remainder of 39, then a+ b = ?

Pipe A can empty a filled tank in 28 hours while Pipe B can fill the same tank, when empty in 35 hrs. If alternatively Pipes A and B are turned on for an hour each time, starting when the tank is full, how long will it take to empty the tank?

The mode of the data 12, 1, 10, 1, 9, 3, 4, 9, 7, 9 is