Quantitative Aptitude - Arithmetic Ability Questions

What is the value of xy if x - y = 3 and x2+y2=15?

The value of x for which the expressions 15 ­ 7x and 15x + 7 become equal is _____.

If 1/6 of x - 7/2 of 3/7 equals - 7/4, then the value of x is

What is the sum of the first 12 terms of an arithmetic progression if the 3rd term is -13 and the 6th term is -4?

The diameters of two cylinders are in the ratio 3:2 and their volumes are equal. The ratio of their heights is

A, B and C can finish a job working alone in 20, 30 and 60 days respectively. They all work together for 1 day, then A and B quit. How many days C working alone will take to finish the remaining part of the job?

If 177 is divided into 3 parts in the ratio 1/2 : 2/3: 4/5, then the second part is

What is that least number that must be added to the product 684 × 686 to make it a perfect square?