Among four books, Book1 is twice as heavy as Book 2. Book 3's weight is half of Book 2's weight. Book 4 is 60 grams more as compared to Book 2 but 60 grams less as compared Book 1. Which book is heaviest?
The age of Ravi is twice the age of Prakash and three times the age of Kumar. If the age of Prakash is 24 years, then what will be the age of Kumar after 4 years ?