6 & 8 8264 2468 5 -16 & +4 15
a. 10 seconds If turn is 360 degrees every 40 seconds, 90 degrees as a right angle would take 1/4 of 40 = 10 seconds b. 84 turns In 56 minutes, the sails make 56/1 * 60/40 turns Again, use of fractions to calculate these types of questions 7,11 & 39