solution.py

# You're playing a game with a friend involving a bag of marbles. In the bag are ten marbles:

# 1 smooth red marble
# 4 bumpy red marbles
# 2 bumpy yellow marbles
# 1 smooth yellow marble
# 1 bumpy green marble
# 1 smooth green marble

# You can see that the probability of picking a smooth red marble from the bag is 1 / 10 or 0.10
# and the probability of picking a bumpy yellow marble is 2 / 10 or 0.20.

# The game works like this: your friend puts her hand in the bag,
# chooses a marble (without looking at it) and tells you whether it's bumpy or smooth. '
# 'Then you have to guess which color it is before she pulls it out and reveals whether you're correct or not.

# You know that the information about whether the marble is bumpy or smooth changes the probability of what color it is,
# and you want some help with your guesses.

# Write a function color_probability() that takes two arguments: a color ('red', 'yellow', or 'green')
# and a texture ('bumpy' or 'smooth') and returns the probability as a decimal fraction accurate to two places.

# The probability should be a string and should discard any digits after the 100ths place.
# For example, 2 / 3 or 0.6666666666666666 would become the string '0.66'. Note this is different from rounding.

# As a complete example, color_probability('red', 'bumpy') should return the string '0.57'.


def color_probability(color, texture):
    marbles = {
        'red': {'smooth': 1, 'bumpy': 4},
        'yellow': {'smooth': 1, 'bumpy': 2},
        'green': {'smooth': 1, 'bumpy': 1},
    }

    return str(marbles[color][texture] / sum(i[texture] for i in marbles.values()))[:4]