4 cards are chosen at random from a deck of 52 cards without replacement. what's the probability of choosing a ten, a nine, an eight, and a seven in order?

What do you mean i don’t understand

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct