In a race between 18 people, how many ways can the top 5 finishers be arranged?

This would use the combination formula, since the order of the people doesn't matter, other than having 5 top finishers.

C(18,5) = 18! / (5!(18-5)!) = 8,568 ways

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!

he has now walked a total of what?

if i know what this is maybe i can

step-by-step explanation: