Brain Teaser – December 24, 2016

Answer: 5 packages of syringes and 3 packages of needles.
Dr. Johnson needs to come up with the smallest number that is divisible by both 6 and 10.
Since 6=2×3 and 10=2×5, the smallest number that is divisible by 6 and 10 is 2x3x5=30.
Therefore, Dr. Johnson needs 30/6=5 packages of syringes and 30/10=3 packages of needles.