18. Consider a standard deck of 52 well-shuffled cards. b) In how many ways can you select five cards if three of them are hearts?
c) In how many ways can you select five cards if only one of them is black?

see below

Step-by-step explanation:

Part A:

d = rt

Solve for r

Divide each side by t

d/t = rt/t

d/t = r

Part B:

665280 ft/ 3 hours = r

221760 ft/ h = r

Part C:

Change to miles per hour

We know 5280 ft = 1 mile

221760 ft/ h * 1 mile/ 5280 ft = 42 miles / hour

Part D:

We should use miles per hour.  The number of ft is too large and the in the US we usually think in miles per hour when we drive