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.

If the digits of a two-digit number are interchanged, the number formed is greater than the orginal number by 45. If the difference between the digits is 5, then what is the orginal 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.