Quantitative Aptitude - Arithmetic Ability Questions

If x -­ y = ­7 and x + y = 13, then x2 - y2 is

What is the area (in sq cm) of a rhombus if the lengths of the diagonals are 12 cm and 14 cm?

B is thrice as efficient as A and C is 0.75 times as efficient as A. What is the ratio of number of days taken by A, B and C when they work individually?

The cube of 997 is

If sin8 θ + cos8 θ – 1 = 0, then what is the value of cos2 θ sin2 θ (If θ ≠ 0 or π/2)?

A can make a cupboard in 10 days and B can do it in 50 days. Along with C, they did the job in 6.25 days only. Then in how many days C alone can do the job?

If 7 times the seventh term of an Arithmetic Progression (AP) is equal to 11 times its eleventh term, then the 18th term of the AP will be

For what sum will the simple interest at R% for 2 years will be R?