arithmetic Questions

Sowmika and Rachana can complete a piece of work in $40\text{days}$ and $60\text{days}$ respectively. Sowmika starts the work alone, and after $4\text{days}$, Rachana joins her to complete the remaining work. In how many days will the entire work be completed?

The average age of a group of $8$ people is $20\text{years}$. One person leaves the group and the average age becomes $18\text{years}$. Find the age of the person who left.

Meena earns $\text{Rs. }9,000$ in a month by working $25\text{days}$. At the same rate, how many days must she work to earn $\text{Rs. }10,800$?

Two numbers are in the ratio $5:7$. If the larger number is $21$, what is the smaller number?

A travelled for $3\text{hours}$ at a speed of $80\text{km/h}$ and then for $5\text{hours}$ at a speed of $120\text{km/h}$. What is the average speed of the journey?

A sum of $\text{Rs. }2,500$ is invested at $8\%$ per annum compounded annually. What will be the amount after $2\text{years}$?

The average of $10$ consecutive odd numbers is $54$. Find the sum of the fifth and seventh numbers.

A mixture contains alcohol and water in ratio $4:5$. If $10\text{litres}$ of water is added to $27\text{litres}$ of the mixture, find the new ratio of alcohol to water.

In a test, the marks obtained by $\text{E}$ is $30\%$ more than the marks obtained by $\text{F}$. If $\text{F}$ scored $20$ marks, how many marks did $\text{E}$ score?

Priya lent $\text{Rs. }3,500$ to her friend at a simple interest rate of $6\%$ per annum. After how many years will the interest amount to $\text{Rs. }1,050$?