Find the forth proportional to $${ x^{2}b^{2}c^{3}}$$, $${ x^{3}bc^{4}}$$ and $${ x^{4}b^{2}c^{2}}$$.

A spherical ball of lead 3 cm in diameter is melted and recast into three spherical balls The diameter of two of these are 1.5 cm and 2 cm respectively. The diameter of the third ball is 

150 workers were engaged to finish a piece of work in a certain number of days. Four workers dropped on the second day, four more workers dropped on third day and so on. It takes 8 more days to finish the work now, find the number of days in which the work was completed?

The ratio between three number is 2 : 3 : 5 and the sum of these number is 275. Find the smallest number.

The ratio of speeds of A is to B is 2:3 and therefore A takes 20 minutes less time than B takes. What is the ratio of time taken by A and B?

The population of a city in the year 2020 was 2,00,000. The rate of growth of population is 8% per annum. Find the population of that city in the year 2022.

A reduction of 20% in the price of rice enables a man to buy 5 kg more for Rs.100. The price of the rice before reduction was-

The simple interest on a certain sum of the money at 4 % per annum for 4 years is Rs.80 more than the interest on the same sum for 3 years at 5 % per annum. Find the sum.