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

This an example problem of arithmetic progression. Where there is a common of difference of 3. So the formula

X = a1 + (n-1) d

Where x = 102 ( because is the first number greater than 100 that is divisible by 3

A1 = is the current amount of marble

N = number of times they need to behave

D = 3

102 = 24 + (n-2) 3

Solving for n = 27 times they need to behave