Dive the total amount of flour by the amount needed for each batch of pancakes.
9/10 / 3/5
When dividing by a fraction flip the second fraction over and change the division to multiplication.
9/10 x 5/3 = (9 x 5) / (10 x 3) = 45/30 = 1 15/30 = 1 1/2 batches
Answer: 1 1/2