4. C and D both are correct
12. H
11. B
Answer:
2 1/6
Step-by-step explanation:
2/3+2/4=8/12+6/12=14/12=1 2/12=1 1/6
1 1/6+1=2 1/6
2/5
Since 12 out of 30 marbles were black, you can assume that the percentage of black marbles in the bag is 40% (Ex: 12/30=.4) The probability that the marble you pick is black is equal to the percentage of black marbles in the bag. 40% is equal to 2/5.
