Why debit / credit cards have 16 digit numbers #LLAShorts 62

Soni has digit cards 1, 4 and 7 . She makes 2 - digit numbers using each card only once The probability that a 2 - digit number chosen at random is divisible by 2 is

From 80 cards numbered 1 to 80, two cards are drawn at random.The probability that the cards have the numbers divisible by 4 is

Number of credit cards held by an individual can be treated as

A box contains card bearing numbers from 6 to 70. If one card is drawn at random from the box, find the porbability that it bears (i) a one digit number(ii) a number divisible by 5.

Find the largest 6-digit number divisible by 16.