Quantitative Aptitude - Arithmetic Ability Questions

The marked price of a pen is Rs 3000. The shopkeeper gives two successive discounts of 15% and a% to the customer. If the customer pays Rs 2142 for the pen, then what is the value (in percentage) of a?

A boat covers a distance of 14 km upstream and 16 km downstream in 9 hours. It covers a distance of 12 km upstream and 40 km downstream in 11hours. What is the speed (in km/hr) of the boat in still water?

If cosA/(1 - sinA) = x, then the value of x is

Find the value of  x3 - y3, if x - y = 4 and xy = 12.

If 3.5x = 0.07y, then find the result of [y-x / y+x]

Find the value of x if 0.08x + 0.04y = 10 and 0.2(x-1) + 0.4y = 24.8

An army lost 10% of its men in war, 10% of the remaining died due to disease and 10% of the rest were declared disabled. Thus the strength of the army was reduced to 7,29,000 active men. The original strength of the army was

If the roots of the equation a(b – c)x2 + b(c – a)x + c(a – b) = 0 are equal, then which of the following is true?