You draw a card at random from a deck that contains 3 black cards and 7 red cards.
What is P(draw a black card)?

The P(draw a black card) is 3/10.

Step-by-step explanation:

It is given that the deck contains 3 black cards and 7 red cards.

Therefore, the total number of cards in the deck = 7 red + 3 black = 10 cards.

Now, we need to find the possible outcomes of getting a black card. So, the number of black cards in the deck = 3 black cards.

The formula to find the probability is given by :

Probability = Number of required event / Total number of outcomes.

Here, the required event is getting a black card out of 10 cards in the deck.

Probability (to draw black card) = 3/10.

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional