the cards are marked with the numbers 6 to 15 and are mixed well before removing one card out.
need to find out :
probability of getting a card with a number less than 10
probability = number of favorable events / total number of events
the number that are below 10 = 4
the total number of cards with all numbers = 10
probability = 4/10
∴ the probability of getting a number below 10 = 2/5