Problema Solution
suppose it take 3 chefs, all working at the same speed, can grate 6.5 carrots, all the same size, in 2.5 minutes. How long would it then take 5 chefs to grate 20 carrots?
Answer provided by our tutors
lets say that one chef can grate 1 carrot in x minutes that is his rate is 1/x carrots per minute
the rate of 3 chefs will be 1/x + 1/x + 1/x = 3/x carrots per minute
3 chefs can grate 6.5 carrots in 2.5 min thus
3/x = 6.5/2.5
x = (3*2.5)/6.5
x = 15/13 carrots per minute
5 chefs will have a rate of 5/x = 5/(15/13) = 13/3 carrots per minute
let t = the time needed for grating 20 carrots
t*(5/x) = 20
t(13/3) = 20
t = 20*3/13
t = 60/13
t = 4 8/60 min
t = 4 2/15 min
t = 4 min 2*60/15 sec
t = 4 min 8 seconds
5 chefs will grate 20 carrots in 4 min 8 seconds.