There are 47 people attending a play at an outdoor theater. There are 11 groups of people sitting in groups of 3 or 5. How many groups of each size are there?
Thanks for the A2A.
We can solve this problem by assuming.
If all of the groups are groups of 3, then there will be 33 people.
5 - 3 is 2.
Because we are 14 people behind, there are 14/2 groups of 5.
That is, 7 groups of 5 and therefore, 4 groups of 3.