1. Three solid spheres have their radii r1, r2 and r3. The spheres are melted to form a solid sphere of bigger radius. Then the radius of the new sphere is
2. The amount of extension in a spring is proportional to the weight hung on it. If the weight of 5 kgs produces an extension of 0.4 cm, what weight would produce an extension of 5cm?
7. Smaller diagonal of a rhombus is equal to length of its sides. If length of each side is 6 cm, then what is the area (in sq.cm) of an equilateral triangle whose side is equal to the bigger diagonal of the rhombus?
8. A solid cone of height 24 cm and radius of its base 8 cm is melted to form a solid cylinder of radius 6 cm and height 6 cm. In the whole process what percent of material is wasted?
10. In triangle PQR, the sides PQ and PR are produced to A and B respectively. The bisectors of ?AQR and ?BRQ intersect at point O. If ?QOR = 50°, then what is the value (in degrees) of ?QPR?