Answer:
the correct answer is 6561
Find the rate in which both balls make one full rotation around the track.
Ball A:

It takes 30 seconds for Ball A to make a full rotation.
Ball B:

It takes 20 seconds for Ball B to make a full rotation.
Find the least common multiple of 20 and 30 to find the time at which they'll meet.
Multiples of 20: {20,40,60}
Multiples of 30: {30,60}
60 is the least common multiple of both 20 and 30.
The balls will meet again at
60 seconds.
Answer: 500
Step-by-step explanation:
it is closest and is under 550. if it were 551 through 599 it would be 600
Answer:
make the denominators ( bottom number ) the same and whatever u do to that do to the top
Step-by-step explanation:
e.g ½ - ⅓
make the common denominator 6
to get from 2 to 6 u times by 3 so it wud be 3/6
and then to get from 3 to 6 u times by 2 so do the same to the numerator (top number) so u get 2/6
3/6 take away 2/6 is 1/6
:)