If $$ {\sqrt{2x+9}+x=13}$$ then find the value of x?

If a=2b/3, b=2c/3, and c=2d/3, then find the ratio of b and d:

In a mixture 25 litres, the ratio of milk and water is 4:1. How many litres of milk must be added to make the ratio 16:1?

Reshma covers 45 km at a speed of 15 km/h by bicycle, 80 km at a speed of 40 km/h by car, and another 6 km at a speed of 2 km/h on foot. Find her average speed for the whole journey (correct to 2 decimal places).

A mixture contains milk and water in the ratio 5: 1. On adding 4 litres of water, the ratio of milk and water becomes 5: 2. What is the quantity of milk in the original mixture?

A and B together can do a piece of work in 16 days and B and C together can do the same work in 24 days. From starting A and B worked for 4 days and 7 days respectively, when A lefts the work then C joins the work and he works for 23 days and complete the work. Then find in how many days will C complete the work alone?

The Value of $$ {\sqrt{6-\sqrt{17-2\sqrt{72}}}}$$ is closest to:

The ratio of the square of volume of two cylinders is a:b and the ratio of their radius is x:y, then what is the ratio of their heights?