R. Gupta Solutions for Exercise 7: MULTIPLE CHOICE QUESTIONS

What should be added to each of the numbers $12, 30, 40$ and $86$, so that they are in proportion:

The mean proportional to $6+\sqrt{27}$ and $6-\sqrt{27}$ is:

If $x:y = 9:11$, the value of $\frac{5x+3y}{3x+5y}$ is:

The ratio of males and females of a village is $5:3$. If there are $800$ males in the village, the number of females is:

In a mixture of $60$ litre, the ratio of ethanol to ether is $4:1$. How much ether must be added to the mixture to make this ratio $2:1$? 

A mixture of $45$ litres of spirit and water contains $20\%$ of water in it. How much water must be added to it to make the water $25\%$ in the new mixture?