The answer would be 3 smoothies.
Lets first turn 3 1/2 cups into an improper fraction, which would be 7/2. Now, in order to find how many 1/4 s are in 7/2, we will have to convert the denominator. What times 7/2 would equal 4 in the denominator? That would be 2. So, 7/2 x 2/2 would be 14/4.
Now to the fun part! How many 1/4 cups are in 14/4 cups? As observed, he can make 3 smoothies out of 14/4 cups of yogurt.
