An airplane travels 6200 kilometers against the wind in 8 hours and 6840 kilometers with the wind in the same amount of time. What is the rate of the plane in still air and what is the rate of the wind?

still air = 815, wind = 40

Step-by-step explanation:

x+y=against

x-y=with

8(x+y)=6200

8(x-y)=6840

Divide 8.

x-y=775

x+y=855

Subtract. 2 from 1

2y=80

y=40

x=815

Hope this helps plz hit the crown :D

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)