Can someone please help me with this problem?

For question one I think there is 5040 different combos.

7!= 7x6x5x4x3x2x1
=5040

A Zoologist wants to investigate how different species of animals interact in a habit. The following animals are chosen:
{Tiger, Lion, Leopard, Jaguar, Cougar, Cheetah, Lynx}

a) In the first investigation, the Zoologist chooses three animals and places them into an enclosure. It is assumed that the order the animals are placed in the enclosure does not affect how they interact with one another. How many experiments are needed to determine how all possible groups of three would interact with one another?
Number of experiments required for investigation 1:

b) In the second experiment, the Zoologist chooses one animal and places it in an enclosure, giving it time to establish teritory. The Zoologist then chooses a second animal and places it in the enclosure. How many experiments are needed to determine interactions between all the animals?
Number of experiments required for investigation 2:

hmm for number 1 its just how many groups of 3 you can choose from 7, theres a special formula for that.

for number 2 the experiment is sequential, and as far as i can see order matters. There are 7 ways to choose the first animal and 6 ways to choose the second. So treating it as one experiment, there are 7*6 possible outcomes and all of them have to be exhausted...

I know there is a formula nCr which is what I used the first time so I guess that would be the correct answer.
For the second one I was torn on because initially I got 49 but I then got 42 and since you have said 7*6 I would imagine that is correct too. I’m not really very confident on that though as this is my worst area of maths

The reason its not 49 is when the first animal is chosen there are only 6 left to choose from. Its like when you are drawing balls from a bag and you dont replace them, the number of options decrease by 1 each time.