Answer:
57.5 marbles rounding to 58 if you do not have partial marbles
Explanation:
The number of marbles is equal to the percent of the marbles times the total number of marbles
23 = 40% total marbles
Change to decimal form
23 = .40 M
Divide by .40
23/.40 = .40M/.40
57.5 = M
This question is odd since you can't have part of a marble
I would round up and have 58 marbles
58 *.40 = 23.2 marbles