There are 13 diamonds in the deck, so 
ways of drawing 3 diamonds.
There is a total of 
ways of drawing any 3 cards from the deck.
So the probability of drawing 3 diamonds is
where 
.
A is the correct answer. When put into calculator, the decimals ends.
a = 4 first term, r = ?, T10 = 100.
Tn = ar^n - 1 formula for g.p
T10 = 4r^ 10 - 1
100 = 4r^9
Divide both side by 4
100/4 = 4/4r^9
25 = r^9 take the 9th root of both side
9√25 = 9√r^9
r = 9√25
To find the nth term
Since Tn = ar^n - 1
