Answer:
24/49
Step-by-step explanation:
The options to get 2 of different color is picking blue then red or red then blue.
Starting with picking blue then red.
The chance to pull blue first is 3/7. Then since the marble is replaced the chance to pull red next is 4/7.
The chance to get those in that specific order is the product of the two fractions. (3/7) * (4/7) = 12 / 49
The second option of getting red then blue will be the same as above but 4/7 then 3/7 with the same result of 12/49.
To finish, add the two probabilities together 12/49 + 12/49 = 24/49.
