Quantitative Aptitude - Arithmetic Ability Questions

What is the average of all numbers between 11 and 80 which are divisible by 6?

What is the average of all numbers between 9 and 90 which are divisible by 8?

The simplified form of (4x + 3)2 . (3x - 5) - (4x3 - 12x2 + 9x - 20) is

The average age of A and B is 18 years. After 3 years, C joins them and the average ages of A, B and C becomes 22 years. The age of C is ?

The rate of simple interest per annum at which a sum of money double itself in 16 2/3 yrs is

A certain bank offers 8% rate of interest on the 1st year and 9% on the 2nd year in a certain fixed deposit scheme. If Rs 17,658 are received after investing for 2 years in this scheme, then what was the amount (in Rs) invested?

If P = 7 + 4√3 and PQ = 1, then what is the value of 1/P2 + 1/Q2?

What is the value of (91 + 92 + 93 + ......... +140)?