Answer:
8 red marbles.
Explanation:
All together we have 40 marbles. The fraction of marbles that are red is 1/5 which means that we should divide the total number of marbles, which is 40 by the denominator ( Bottom number of fraction ) 5 so that we get the number of groups that have 1 red marble in them. In this case we have 8 groups.
40/5=8
You always divide by the denominator ( Bottom number of fraction ) first and then you multiply your answer by the numerator ( Top number of fraction ) .
If each group has 1 red marble in it and we have 8 groups, it means that we have 8 red marbles in the bag.
1 * 8 = 8 red marbles in the bag
If the numerator (number above the fraction line) was more than one, then this would mean that we have more than 1 marble in each group of marbles.
Example:
If we had 3/5 we would have 3 marbles in each group of marbles. This means that instead of doing 1 * 8 we would have to do 3 * 8 = 24. We would have 24 red marbles in the bag.
Easy and quick way if you do not need the explanation:
Another way we could do this is by simply multiplying the fraction ( 1/5 ) by the total number of marbles ( 40 ). This would still give us an answer of 8 red marbles in the bag. 40/5=8, 8*1=8