"Combinations" isn't really the right word, because a combination doesn't take order of elements into account, and the outcome of a race certainly does depend on order. "Permutations" would be the correct term.
If 4 students are competing, then the race has
4! = 4 • 3 • 2 • 1 = 24
possible outcomes.
Answer:
15 and 25
Step-by-step explanation:
15+25=40
10+20=30+5+5=10+30=40
Answer: 1 3/5
Step-by-step explanation:
5/5 = 1
There is a remainder of 3/5.
Combine these two pieces to get the whole, 1 3/5.