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?

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

A kite is flying at a height of 50m. If the length of string is 100m then the inclination of string to the horizontal ground in degree measures is:

P can do a piece of work in 60 days & Q can do the same work in 50 days. Find the ratio of working efficiencies of P to Q.

10 persons can do a job in X days. If 20 persons with twice the efficiency can do the same job in 5 days, then find the value of X?

Triangle PQR is such that PQ=9 cm, QR=6 cm, PR=7.5 cm and triangle PQR is similar to triangle XYZ. If XY=18 cm, find the value of YZ.

A wholesaler purchased 7 hair clips for a rupee. How many for a rupee must he sell to get profit of 40%?

Aparna changes the marked price of an item to 50% above its C.P. What % of discount allowed in approximately to gain 10%?