Answer:
14 hrs of babysitting and 6 hrs of tutoring
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.
the example of an open equation is :x+9=16
Answer:
9+x<12
Step-by-step explanation:
add 9 to an unknown number.
9+x
use the < less than symbol (instead of an equal sign) and write 12.
3n + 7 ><span> 4n
-3n -3n
7 > n
n</span> < 7