Question

A clown needed 275 balloons for a party he was going to, but the balloons only came in packs of 2.How many packs of balloons does he need to buy?

Answer 1

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