Question

Mrs. Morton has a special reward system for her class. When all her students behave well, she rewards them by putting 3 marbles into a marble jar. When the jar has 100 marbles or more, the class has a party. Right now, the jar contains 24 marbles.

Answer 1

So 86 more marbles are needed in order for the class to receive a party

Answer 2

$24 + 3r \geq 100 \ |-24 \\\\ 3r \geq 76 |:3$

$r \geq 25\frac{1}{3}\\\\ so\\\\ r=26$

Answer:
26 times

24 + 3 * 26 = 24 + 78 = 102 
 and party :)