Answer:
Permutation:
The number of ways Jake can join the field trip with his classmates can be represented as a permutation since the order in which they join the field trip matters. Assuming that Jake and his classmates are the only ones who will join the field trip, the number of ways Jake can join the field trip is:
1 * 1 = 1
Therefore, there is only one way for Jake to join the field trip.
Combination:
The number of ways to sell the pens can be represented as a combination since the order in which the pens are sold does not matter.
There are two boxes of red pens and two boxes of black pens, so there are a total of four boxes of pens. Each box contains 15 pens, so there are a total of 60 pens. We can choose the number of red pens we want to sell from the two boxes of red pens, and the number of black pens we want to sell from the two boxes of black pens. The number of ways to choose the number of red and black pens can be calculated using a combination:
Number of ways to sell pens = C(2,1) * C(2,1) = 2 * 2 = 4
Therefore, there are 4 ways to sell the pens.