A set of four postcards costs $1.00. Single postcards cost $0.50. What is the least amount of money you can spend to buy exactly 15 postcards?

3 Sets of the 4 post cards and 3 of the single post cart sets.

Step-by-step explanation:

You buy 3 of the 4 post card set becuase that is the most you can get of those to get under 15 post cards.

You would now have 12 postcards now you have to buy 3 of the single set to get to 15 cards

step-by-step explanation:

45.36 feet per second

step-by-step explanation:

tyrone travels 30 miles in 58.2 minutes.  

1 mile = 5280 feet; this means he travels

30(5280) = 158400 feet in 58.2 minutes.

1 minute = 60 seconds; this means he travels 158400 feet in

58.2(60) = 3492 seconds.

this gives us the unit rate of

158400/3492 = 45.36 feet per second.