Answer:
They studied for a little more than an hour?
Step-by-step explanation:
7/12 of 60 Mins is 35 mins and 2/3 is 40 mins 40+35=75 mins
which is a little more than an hour, 15 mins more to be precise.
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: According with the graph, the input value for which the statement f(x)=g(x) is true (the value of "x" where the graph intersect) is 1.5 (third option).
Solution
The input value for which the statement f(x) = g(x) is true, is the value of "x" where the graph of the two functions intersect. Accordind with the graph, the two functions f(x) and g(x) intersect at x between 1 and 2, approximately at x=1.5
It should be B If I am correct if I am not I am sorry