Quantitative Aptitude - Arithmetic Ability Questions

If cosA + cos2A = 1 then the value of sin2A + sin4A is

A new topic named Problem Solving was also introduced and it was decided that 10% time of all topics except Arithmetic will be devoted to it. What will be the central angle (in degrees) made by Problem Solving in the new pie chart?

A can do a work in 24 days and B in 40 days. If they work on it together for 10 days, then what fraction of work is left?

The sum of the ages of Rohit and Ankit is 78. Rohit's age is twice the age of Ankit. What is the age (in years) of Rohit?

If -3/2 + (2/3)(3x + 9) = x/2, then what is the value of x?

If Cos θ = 5/13, then Cosec θ = ?

If A and B are the roots of the equation Ax2 – A2x + AB = 0, then what is the value of A and B respectively?

If a + b = 1 and ab = -6, then what is the value of a3+ b3?