Quantitative Aptitude - Arithmetic Ability Questions

The mean deviation of the data 3, 10, 10, 4, 7, 10, 5 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 a:b = 3:8, find the value of (5a ­ 3b)/(2a + b).

If 2x + 3y = 0 and 3x ­- 4y = 34, then x ­- y = ______

If the shopkeeper sells an item at Rs 960 which is marked as Rs 1200, then what is the discount he is offering?

The sum of two positive integers is 80 & difference between them is 20. Then what is difference of squares of those numbers ?

If the amount received at the end of 2nd and 3rd year at Compound Interest on a certain Principal is Rs 1,800, and Rs 1,926 respectively, what is the rate of interest?