Answer:
3 types of speakers must be there.
Explanation:
If Genevieve is choosing between 5 types of stereos and 2 types of amplifiers, that means, she has 10 options available to choose, because
. The total number of combinations is found with a product because there are different types of stuff, like choosing between pants and shirts.
Now, if we has 10 possible ways to choose, and she finally makes 30 choices, the type of speakers can be found by dividing the total 30 choices by the 10 possible

Therefore, there must be 3 types of speakers.