Yan can read two pages in 3 minutes. At this rate, how long will it take him to read a 360-page book?
Using the ratio pages/minutes, the proportion 2/3 = 360/x can be used to find the time. Cross multiply. 2x = 3 × 360, so 2x = 1,080 and x =1080/2 = 540 minutes. Convert minutes to hours. There are 60 minutes in 1 hour so 540/60 = 9 hours.