A box of crayons has 12 different coloured crayons in it. 4 crayons are given to one child to play with, then another 4 are given to a second child to play with, and finally
the last 4 are given to a third child. In how many was can these crayons be
distributed?

  34,560

Step-by-step explanation:

Total crayons of different color = 12

Total children = 3

Each child will get 4 crayons.

Number of combinations of selecting r things out of n things =

The number of ways of selecting the first 4 crayons for first child =

Colors left = 12-4 =8

Now, the again selecting 4 colors out of 8 for second child =

Colors left =4

Number of ways of selecting 4 colors out of 4 for third child  =1

Total number of ways = 495 x 70 x 1 = 34650   [By fundamental principle of counting]

Hence, the total number of ways = 34,560.

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.