a dog shelter had 20 puppies last month. This month, 31 puppies are at the shelter. What is the percent of change?

Simple, finding markup, you'll use two equations Markup=New-Original Markup%=Markup/Original*100 Markup=31-20 Markup=11 Then, Markup%= 11/20*100 M%=0.55*100 M%=55% Thus, the percent of change was, 55%.