Juan plans to build a bookcase to store his paperback books, DVDs, and CDs. He has lumber that he will use for the sides and the back of the bookcase. The bookcase will have five shelves, and each will be 2 1/2 long. Does he have enough lumber to make the five shelves?

Juan does not have enough lumber to make the five shelves.

Step-by-step explanation:

Let assume that:

If Juan bought a piece of lumber that is 18 feet long.

and the bookcase will have = 5 shelves

Also, the length of each bookcase = 2 1/2 long = 2.5 long

Then the amount required for the five shelves = 5 × 2.5

= 12.5 feet long

Therefore, we can say Juan does not have enough lumber to make the five shelves.

Hence, he will need an addition of: (18 - 12.5) feet = 5.5 feet piece of lumber

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.