Quantitative Aptitude - Arithmetic Ability Questions

There were 24 studentsina class. One of them, who was 18 years old, left the class and his place was filled up by a new comer.Ifthe average of the class was thereby lowered by 1 month, the age of new comer is-

A and B together do a job in 15 days and A alone could do the same job in 20 days. How many days would B take to do half the job if he worked alone?

What is the sum of the first 9 terms of an arithmetic progression if the first term is 7 and last term is 55?

What is the length of the side of an equilateral triangle, if its area is 36√3 sq cm?

If √(cosec2A - 1) = x, then the value of x is

ΔPQR is right angled at Q. If cosP = 5/13, then what is the value of cosecR ?

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

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