Mrs. Stephens had to stop for a total of 8 red lights. Think about the problem like this. Imagine 36 intersections and how many times 16 is divisible. Within 36 intersections, Mrs. Stephens will go through 16 intersections at least twice with 4 left over [not needed]. When red lights appear at 4 of every 16 intersections,
Mrs. Stephens will pass 16 intersections twice, 4 lights [per 16] x 2 [16 intersections] equals 8 stops at a red light.
