Answer:
Not enough information
Not enough information
32 marbles
Explanation:
The following is what we know about the problem:
In the bag:
Total number of marbles = unknown
Number of yellow marbles = 20
Number of black marbles = uknown
Chosen:
Number of yellow marbles = 7/10 of 20
Number of black marbles = 18
Now for the first two questions, the number of black marbles in the bag needs to be given to find out how many marbles were not chosen in the bag and how many black marbles were not chosen. Since it was not given, we cannot determine the first two.
As for the last one, it asks, "how many marbles in the bag were chosen". Since we know how many of each color were chosen, then it is possible to answer.
Number of yellow marbles = 7/10 of 20
All you need to do is solve how many marbles is 7/10 of 20. We do this by multiplying the fraction by the whole.
So we now know that 17 out of the 20 marbles were chosen.
The number of black marbles chosen was already given, which is 18 black marbles. We just add them together:
14 + 18 = 32 marbles