If P : Q = 4 : 5 and P : R =2 : 3, then what is 3P : 4Q : 5R?

If pq+qr+rp=0 then find the value of $$ {p^{2}\over {p^{2}-qr}}+{q^{2}\over {q^{2}-rp}}+{r^{2}\over {r^{2}-pq}}$$

By increasing the radius of a sphere by 50 percent, how much will the area of its surface increase?

From a solid cylinder whose height is 12 cm and diameter 10 cm a conical cavity of same height and same diameter of the base is hollowed out. The volume of the remaining solid is (cm³)approximately .Π=22/7

Study the following pie-diagrams carefully and answer the question given below it.
PERCENTAGE COMPOSITION OF HUMAN BODY 

What percent of the total weight of a human body is equivalent to the weight of the proteins in the skin in a human body?

A alone would take 6 hours more to complete the job than if both A and B would work together. When B worked alone he took 1.5 hours more to complete the job and A and B worked together. How much time they will take if they if they work together?

A housewife saved ₹ 2.50 in buying a dress on sale. If she spent ₹ 25 for the dress, approximately how much percent she saved in the transaction? 

Find measure of central angle of the arc whose length is 22 cm and radius of the circle is 28 cm?