Find a number whose double is 45 greater than its half.

A number whose double is 45 greater than its half is : Options are (a) 52 (b) 45 (c) 40 (d) 30.

If a quarter of a number be added to one-third of the number,the result is 20 greater than half of the number.find the number.

20 cards whose number are from 1 to 20 are mixed after placing in a box. A card is drawn at random and it is found that the number on the card is greater than 11. Find the probability that the number on the card is an even number.