Quantitative Aptitude - Arithmetic Ability Questions

Simple interest on a certain sum of money for 3 years at 10% per annum is half the compound interest on Rs 6000 for 2 years at 10% per annum. The sum placed on simple interest is

Of the 3 numbers whose average is 70, the first is 1/9 times the sum of other 2. The first number is

If y=2-x1+x, then what is the value of 1y+1 + 2y+1y2-1 ?

If cosA = x, then x is

If x , y, and z are real numbers such that (x - 3)2 + (y - 4)2 + (z - 5)2 = 0 then (x+y+z) is equal to

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

If a retailer offers a discount of 28% on the marked price of his goods and thus ends up selling at cost price, what was the % mark up?

What is the area of the sector whose central angle is 90° and radius of the circle is 14 cm?