A solid metallic cylinder of base radius 3 cm. and height 5 cm. is melted to form cones, each of height 1 cm. and base radius 1 mm. The number of cones is -

A sum of money was lent at 10% per annum, compounded annually, for 2 years. If the interest was compounded half - yearly, he would have received Rs.660.75 more. Find the sum.

If the areas of circular ring having inner and outer radius 8 cm and 12 cm respectively is equal to the total surface area of cylinder of radius R₁ and height h, then h in terms of R₁ will be :

The price of an article is reduced by 25% but the daily sale of the article is increased by 30%. The net effect on the daily sale receipts is

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

A can write 75 pages in 25 hrs. A and B together can write 135 pages in 27 hrs. In what time can B write 42 pages?

Running 4/3 of his usual speed, a person improves his timing by 10 minutes. Find his usual time to cover the given distance.

A train travelling at 48 km/hr crosses an another train half of its length and travelling in opposite direction at 42 km/hr in 12 seconds. It also passes a railway platform in 45 seconds. The length of the railway platform Is