Answer:

Explanation:
Let r represent the number of additional times the class is rewarded by Mrs. Morton.
We have been given that when all students of Mrs. Morton's class behave well, she rewards them by putting 3 marbles into a marble jar. So marbles added in r additional times would be
.
We are also told that right now, the jar has 24 marbles. So total marbles in the jar would be
.
Since the students have a party, when the jar has 100 or more marbles, so for having a party for the students total number of marble should be greater than or equal to 100.
We can represent this information in an inequality as:

Therefore, our required inequality would be
.