A cyclist went on 4 rides this week, each ride covering 3 miles. On Tuesday, he rode at a speed of 6 miles per hour. He rode at 4 miles per hour on Thursday, 3 miles per hour on Saturday, and 2 miles per hour on Sunday. If the cyclist had always ridden at 4 miles per hour, he would have spent less time cycling. How many minutes less?
30
35
45
50
60
