For the first digit you are choosing from 2 digits
for the second digit you are choosing from 2 digits
for the third digit you are choosing from 2 digits
2*2*2=8
111
110
011
101
000
001
100
010
However......
A number doesn't usually start with a 0 or 0s.
Therefore, if you want 3-digit numbers and not just permutations using 0 and 1, then you must eliminate
011, 000, 001, and 010
Seeing that the first digit can't be 0, you choose from 1, then 2, and then 2 digits again; 1*2*2=4 numbers
You choose which answer best suits your problem.
Answer:
A
Step-by-step explanation:
<span>speed = distance/time
total time is 8 hours
outgoing speed is 160 km per hour,
so time = d/160
</span><span>returning speed is 240 km per hour,
so time = d/240
d/160 + d/240 = 8
3d/480 + 2d/480 = 8
5d/480 = 8
5d =480 (8)
5d = 3840
d=3840/5
d=768
answer: so the distance is 768 km</span>
