Quantitative Aptitude - Arithmetic Ability Questions

Twenty one times of a positive number is less than its square by 100. The value of the positive number is

Find the simple interest on Rs. 50 for 6 months at the rate of 10 paise per rupee per month.

A sum of Rs 4000 becomes Rs 7000 in 6 years at simple interest. If the rate of interest becomes double of itself, then what will be the amount (in Rs) after 6 years?

What is the equation of the line perpendicular to the line 5x + 3y = 6 and having Y-intercept -3?

The areas of two similar triangles ΔABC and ΔPQR are 36 sq cms and 9 sq cms respectively. If PQ = 4 cm then what is the length of AB (in cm)?

The radii of two concentric circles are 68 cm and 22 cm. The area of the closed figure bounded by the boundaries of the circles is

A boat covers 143 km upstream in 13 hours and the same distance downstream in 11 hours. What is the speed (in km/hr) of the boat in still water?

In the following question, select the odd word from the given alternatives.