To determine how many cups of sugar Keerthi needs to make 6 cakes, we'll start by finding the amount of sugar needed for one cake and then multiply it by 6.
Keerthi needs 1 1/2 cups of sugar for one cake. To convert the mixed number 1 1/2 to an improper fraction, we multiply the whole number (1) by the denominator (2) and add the numerator (1), resulting in 3/2 cups of sugar needed for one cake.
Now, we can multiply this amount by 6 to find the total cups of sugar needed for 6 cakes:
(3/2) * 6 = 18/2 = 9 cups
Therefore, Keerthi needs 9 cups of sugar to make 6 cakes for her friends.