Quantitative Aptitude - Arithmetic Ability Questions

If x = a cosθ+ b sinθ and y = b cosθ- a sinθ, then x2 + y2 is equal to

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

Among four students sitting in a row, average age of last three students is 20 years and the average age of first three students is 21 years. If the age of first student is 26 years, then what is the age (in years) of the last student?

Rs. x invested at 8% simple interest per annum for 5 years yields the same interest as that on Rs. y invested at 7.5% simple interest per annum for 6years. Find x : y.

What is the simplified value of (cos A + sin A)(cot A + tan A)?

The distance between the points (4, 8) and (k,-4) is 13. What is the value of k?

A and B can do a piece of work in 18 days, B and C in 24 days, A and C in 36 days. Working together they can do the work in

K is 5 years older to H. H is 3 years younger to R. R is 6 years older to C. C is 7 years younger to L. Who is the eldest?