Answer:
It would take 15 students 6 days to weed the school compound
Explanation:
This first step to solving this question is to break down the given rates.
We are told that 10 students take 9 days to weed the school compound. From here we can simplify this by figuring out how long it would take 1 student to weed the compound. Having less people would mean taking a longer time.
1 person is a 1/10 of 10 people. Since we have 10x less people, it should take 10x as long. Therefore it would take 1 person 9x10=90 days to weed a school.
Now the question asks how long it would take 15 people. 15 people is 15x as many as 1 person, so it should take 15x less time to weed the compound. 90/15 = 6
It would take 15 students 6 days to weed the school compound.
Similarly you could have just divided 9 by 1.5 as 15 is 1.5x10, but it is easier to explain the process using the above method.
Hope this helped!