<h3>18 months will pass before the two friends have the same hair length</h3>
<em><u>Solution:</u></em>
Let "x" be the number of months
Joni’s hair is 13 inches long and grows at an average rate of ⅔ in per month
Her friend Kate’s hair is 16 inches long and grows at an average rate of ½ in per month
<em><u>For two friends to have the same hair length, eqn 1 must be equal to eqn 2</u></em>
Thus 18 months will pass before the two friends have the same hair length