Mathematical Sk...

Two solutions of acid and water containing acid and water in the ratio 2 ∶ 7 and 4 ∶ 5, respectively are mixed in the ratio 2 ∶ 5. What is the ratio of acid and water in the resulting solution?

The price of an article is first increased by 20% and later decreased by 25% due to decrease in sales. Find the net percentage change in the final price of the article.

If a certain sum of money becomes 9 times itself in 2 years. Find the rate of compound interest.

What is the compound interest on a sum of Rs. 16000 at 30% per annum for an year if compounded half-yearly?

A man sold two chairs for Rs. 800 each. On one he profit 20% and on another he loses 20%. How much does he profit% or loss% in the whole transaction?

The speed of a boat in still water is \(20\) km/h, and the speed of the stream is \(2\) km/h. In how many hours would the boat cover a distance of \(198\) km downstream?

After how many years, a sum of money at simple interest amount to thrice itself at the rate of \(8 \%\) per annum interest?

The cost price of 50 Coca-Cola Bottles is equal to the selling price of 40 Coca-Cola Bottles. Find the Profit/Loss percentage.

From the top of a lighthouse \(70\) m high with its base at sea level, the angle of depression of a boat is \(15^{\circ}\). The distance of the boat from the foot of the lighthouse is:

A box has 210 coins of denominations one-rupee and fifty paise only. The ratio of their respective values is 13 : 11. The number of one-rupee coins are: