He payed 0.72
First you take 2.88, then you multiply it by 1/4 or a simpler way would be to divide 2.88 by 4. The answer is $0.72
There are 52 cards in the deck.
Picking a spade would be 13/52 which reduces to 1/4
After the first card is picked there are 51 cards left, picking a club would be 13/51
Picking both would be 1/4 x 13/51 = 13/204
The answer is C.
Answer:
Proof for 
Step-by-step explanation:
We are given that a, n, b, r and k are integers.
Also,

Since k divides a and b, we can write,
a = rk and b = sk, where r and s are integers.
Now, we have to prove that k divides r as well that is 
Putting value of a and b in the equation, we get:

Since, (r-sn) is an integer, k divides r.
I think the answer would be 36.5. I divided 4.38 by .12
35-15 i think dont hate me if im wrong