If the angle of elevation of the Sun changes from 30° to 45°, the length of the shadow of a pillar decreases by 20 meters . The height of the pillar is:
A milkman makes 20% profit by selling milk mixed with water at Rs.9 per litre. If the cost price of 1 litre pure milk is Rs.10, then the ratio of milk and water in the said mixture is
Sudha bought 80 articles at the same price. She sold some of them at 8% profit and the remaining at 12% loss resulting in an overall profit of 6%. The number of items sold at 8% profit is: