Quantitative Aptitude - Arithmetic Ability Questions

Twenty one times of a positive number is less than its square by 100. The value of the positive number 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?

Find the odd word/letters/number pair pair from the given alternatives.

A man spends 15% of his income. If his expenditure is Rs. 75, his income (in rupees) is:

If A : B = 3 : 4 and B : C = 6 : 5 then A : (A + C) is

ΔDEF is right angled at E. If cosD = 8/17, then what is the value of secF ?

If (tanA ­- tanB)/(1 + tanAtanB) = x, then the value of x is

Which of the following is not a quadratic equation?