Justin needs to collect one flower for each classmate that is in his 2nd-grade class. It takes him on average 10 minutes to find a flower he likes. He has been gathering for 2 hours. Assuming he has lost 3 of the flowers he initially gathered, how many more minutes does he need to look if he has 30 classmates?
Thoughts? Step-by-step reasoning:
If he gathers for 2 hours, the number of minutes gathering is 2 * 60 minutes per hour = 120 minutes of gathering flowers. Gathering for 120 minutes / 10 minutes per flower = 12 flowers gathered. If he gathers 12 flowers initially but lost 3, he has 12 - 3 = 9 flowers gathered and kept. Since he has 30 classmates total and has 9 flowers, he needs to gather 30 - 9 = 21 more flowers. Assuming it takes 10 minutes per flower, it will take him 10 * 21 = 210 minutes to gather the remaining 21 flowers needed.
Thus, the answer is 210.