Find the 91st term of the arithmetic sequence 28, 8, -12, ...

Step-by-step explanation:

The explicit formula for an arithmetic sequence is

where n is the position of the number in the sequence, a1 is the first number in the sequence, and d is the common difference between the numbers.  

If we are looking for the 91st term, our n = 91;

our a1 is 28, and

the common difference is -20.  Putting all that together gives us the explicit formula for this sequence:

and

and

so

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.