According to the question, the face cards are removed from a full pack of 52.
By using the formula of probability, we get,
P (E) = favourable outcomes / total possible outcomes
Four cards are drawn from the remaining 40 cards, and we must calculate the probability that they are all of the different suit.
Total possible outcomes of drawing four cards are ${}^{40}C_4$
$n (S) = {}^{40}C_4 = 91390$
Let E be the event that 4 cards belong to different suit.
$n (E) = {}^{10}C_1{}^{10}C_1{}^{10}C_1{}^{10}C_1 = 10000$
P (E) = n (E) / n (S)
= 10000 / 91390
= 1000/9139