Quantitative Aptitude - Arithmetic Ability Questions

Identify the odd one out from the following:

If cos 2π/3c = x, then the value of x is

Rathin is now 16 years old while his cousin is 7 years. After how many years will Ratin's age be 1.5 times that of his cousin?

If (secA - tanA)2 = x, then the value of x is

Find the radius of the circle if the length of its arc is 33 cm whose corresponding central angle is 90° ?

In triangle ABC, ∠ABC = 15 deg. D is a point on BC such that AD = BD. What is the measure of ∠ADC (in degrees)?

In what time will Rs.4400 become Rs.4576 at 8% per annum interest compounded half-yearly?

The average revenues of 7 consecutive years of a company is Rs 79 lakhs. If the average of first 4 years is Rs 74 lakhs and that of last 4 years is Rs 86 lakhs, what is the revenue for the 4th year?