Ratio and probability?

Question

a deck of cards contains red and black cards in the ratio 4:3 . if a card is picked at random what is the probability that it is red

Answer

You would pick a red card 4 times out of seven, and a black card three times out of seven.

Answer

A deck of cards contains red  and black  cards in the ratio 4:3 .

r := number of red cards
b :=  number of black cards
n := r + b

Therefore, n is an integer multiple of 7 = 4 + 3.

if a card is picked at random what is the probability P that it is red?

P(r) = 4 / 7 = 0.5714... = 57.14%.

Ratio and probability?

Answers (2)