Question

What type of counting problem is this?
If John has an apple, an orange, a pear, a banana, and a kiwi at home and he wants to bring two fruits for lunch, how many different pairs of fruit can he bring to school?

Answer 1

Step-by-step explanation:

With six different fruits, the first (apple) can be matched with each of the other five. That’s five pairs. The second fruit (orange) can also be matched with each of the other five fruits, except that it has already been matched with an apple, so that would not be a “different” pair. So that’s four more pairs. The third fruit (pear) can make three more “different” pairs, the fourth fruit (strawberry) can make two more unique pairs, and the kiwi and banana make one more “different” pair.

5+4+3+2+1 = 15.