Quantitative Aptitude - Arithmetic Ability Questions

A tyre is sold at three successive discounts of 20%,30%, and 20%. What is the net discount (in percentage)

If sinC - sinD = x, then value of x is

Mansukh can do a piece of work in 10 hours. If he is joined by Jayanti who is 50% more efficient, in what time will they together finish the work?

What is the rate of interest (in %) if simple interest earned on a certain sum for the 3 years is Rs 6,000 and compound interest earned for 2 years is Rs 4,160?

If a wholesaler, sells a tin of coffee at Rs 528 he faces a loss of 12%. Now if he decides to sell it at Rs 636, what will be the profit (in %)?

P and Q are two alloys which are prepared by mixing tin and lead in the ratio of 12 : 5 and 4 : 3 respectively. If equal quantities of alloys are melted to form athird alloy R, then what is the ratio of tin and lead in alloy R?

The standard deviation of the set {10, 11, 9, 11, 9} is

Ravi invested Rs.P in a scheme A offering simple interest at 10% p.a. for two years. He invested the whole amount he received from scheme A, in another scheme (B) offering simple interest at 12% p.a. for five years. If the difference between the interests earned from schemes A and B was Rs. 13,00/, what is the value of P ?