Quantitative Aptitude - Arithmetic Ability Questions

If x - y = -8 and xy = 45, then (x2 + y2) is

The 2nd and 8th term of an arithmetic progression are 17 and -1 respectively. What is the 14th term?

What are the co­ordinates of the centroid of a triangle, whose vertices are A(­2,­5), B(4,­4) and C(7,3)?

What should be added to 3(x­ - 2y) to obtain 2(3x + y) -­ 5(2x + 3)?

The average weight of P, Q and R is 71 kg. If the average weight of P and Q be 66 kg and that of Q and R be 76.5 kg, then the weight (in kg) of Q is.

What is the average of 90, 250, 240, 204, and 616?

A and B can complete a task in 20 days, B and C can complete it in 30 days while C and A can do the same task together in 24 days. How many days will each of and C take to complete the task individually? 

Vikash purchased 5 bananas for Rs.4 and sold 4 bananas for Rs.5. Calculate his % profit?