Suppose x coins are tossed. write an expression to represent the number of possible outcomes.

Step-by-step explanation:

One coin tossed:

Total outcomes = {H,T} =2

Two coins tossed:

Total outcomes :{HH,HT,TH,TT} = 4

Three coins are tossed:

Total outcomes : {HHH,HHT, HTT,TTT,THH,TTH,THT,HTH} =8  

So, 1 coin tossed

      2 coins tossed

      3 coins tossed

Continuing in this manner ..

      x coins tossed

Thus an expression to represent the number of possible outcomes when x coins are tossed :

step-by-step explanation:

what grade level is this? need to know so i can look in my old textbooks!

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.