Quantitative Aptitude - Arithmetic Ability Questions

In the following question, select the odd letter/letters from the given alternatives.

ΔABC is right angled at B. If m ∠A = 60°, then what is the value of 1/√3 Cosec C?

Find two numbers such that their mean proportion is 12 and third proportion is 768.

Given that the polynomial (x2+ ax+ b)leaves that same remainder when by (x –1) or (x + 1) What are the values of a and b respectively?

If 192 pens cost is Rs.10, how many pens can be bought for Rs.5?

Which of the following numbers is a perfect square?

One of the two inlet pipes works twice as efficiently as the other. The two, working alongside a drain pipe that can empty a cistern all by itself in 8 hours, can fill the empty cistern in 8 hours. How many hours will the less efficient inlet pipe take to fill the empty cistern by itself?

A, B and C can do a job working alone in 6, 9 and 18 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to complete the remainder of the job?