Can you explain how to solve theses questions ? I can't understand .35 and 36

35 When Arban walks from home to class, he burns 4.2 calories per minute, and when he rides his bike from home to class, he burns 5.1 calories per minute. If Arban spent a total of 2 hours walking and bicycling from home to class in a week and burned a total of 531 calories, how many minutes did he spend walking? 4 +5 . 1 9 = 531 36 W Note: Figure not drawn to scale. In the circle shown, point O is the center, and diameter ux bisects WY at point Z. The radius of the circle is 6, and XZ=2 . If wz = Vx, what is the value of x