2/3 of 21=? who wants to answer

14

Step-by-step explanation:

Hope this helps!

14

Step-by-step explanation:

Convert 21 to a fraction: 21/1

2x21= 42

3x1= 3

42/3= 14

3/3= 1

14/1 --> simplify to 14

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.