For this case what you need to know is that each package contains 2 balloons. Therefore, you can solve the problem by making the following rule of three: 1 package ---> 2 balloons x ---------------> 275 balloons Clearing x we have: x = (275/2) * (1) x = 137.5 Nearest whole number: x = 138 Answer: I need to buy 138 packs of balloons
