Suppose we have 2 bags. Bag 1 contains 3 red and 7 green balls. Bag 2 contains 4 red and 8 green balls. A person tosses a coin and if it is heads goes to bag 1 and draws a ball. If it is tails, he goes to bag 2 and draws a ball.
Given that the ball draw is red, then what is probability that it came from bag 1?
$0.317$ or $0.4737 \ ?$