Question

A bag contains n cards each having one of the numbers (1,2,3,4,...,n) written on it. If all numbers are used the probability of drawing a card with a number less than or equal to 10 is 4/10. How many cards are in the
bag?

Answer 1

The set should be
{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, \
20, 21, 22, 23, 24, 25}

10/25=40/100=4/10