Question 891499
Let's put in some numbers.
The baker made 200 cookies which fed 5 students for 10 days. How many days would it take 15 more students to eat the same amount of cookies? 


200/5=40 c/s
40/10= 4 cookies a day c/10s cookies per day
add 15 students
200/20=10 c/(s+m)
10/4=2.5 days (c/(s+m))/(c/10s) 
c=200 s=5  m=15
(c/(s+m))/(c/10s)=10s/(s+m)
10s/(s+m)