1)For numerate the pages of the book used 700 digits. If the book starts from page 3, determine how many pages are in this book. 2)In a party concert 11 singers sang a song. Every singer sang one song in pair with other singers. How many songs were sang? 3)The train «London – Manchester» stops on 21 stations. The tickets to the train depend from the distance between stations. How many types of tickets must print with different prices? 4)The truck’s tank has capacity of 200 liters, it is filled with fuel by 30%. During the trip fuel has decreased by 45%. How many liters of fuel left after trip? PLEAS