Suppose the tax rules allow a person to either pay 20% of their total annual income as income tax, or pay 25% after claiming a deduction of Rs 2 lakh from the total annual income. What is the lowest annual income above which the former regime is attractive to the taxpayer?

A factory kept increasing its output by the same percentage every year. Find the percentage if it is known that the output has doubled in the last two years. (assume $\sqrt{2} = 1.4142$)

Shalini got $30\%$ of the maximum marks in an exam. She failed by $50$ marks. Malini scored $40\%$ of the maximum, and this score was $20$ marks more than the pass mark. What is the pass mark?

A foreign country reduces its import duty on an Indian exporter's product from 30% to 10%. The exporter estimates that the reduction in import duties - which he will pass on fully by reducing prices -- will increase the volume of sales by 50%. The revenue obtained in that market turned out to be Rs 165Cr. What would the revenue have been if the exporter continued selling at the old price?

A firm projects its revenue to rise 20% in each of the next 3 years. At the same time, it projects costs to rise 10% each year. If profit this past year was Rs 10Cr on revenue of Rs 100 Cr, what will be the accumulated profit at the end of the 3rd year?

An exporter estimates with certainty that a $26\%$ higher price for his product will decrease the volume of sales in a foreign market by $30\%$. After having to increase the price by $26\%$, the revenue obtained from sales in that market turned out to be $\text{INR } 44.1 \text{ Cr}$. What would the revenue have been if the exporter had been allowed to sell at the old price?

One country's GDP is currently $600 billion and is growing at 10% per annum. Another country's GDP is $700 billion, while it is growing at 5% per annum. How many years will it take for the GDP of the 1st country to overtake the 2nd?