Question

how many even numbers are there with 3 digits so that if 5 is one of the digits,then 7 is the next digit?

Answer 1

If 3digit even numbers start with 5 then next digit is 7.So numbers are570,572,574,576,578=5 numbers. Other 3digits numbers can be formed as (1) unit digit can be taken from0,2,4,6,8 i.e 5 ways.