Posted by Zayn on .
Machine X can pack 3 crates of bottles and Machine Y can pack 4 crates of bottles within the same time. In half an hour, Machine X packs 24 crates. How many crates can 12 Machine Y s pack in 1 hour?

Maths 
Reiny,
machine X can pack 48 crates per hour
since ratio of machine X : machine Y = 3 : 4
48 : machine Y = 3 : 4
3 machine Y = 192
machine Y can pack 64 crates per hour
(note 48:64 = 3:4)
so 12 machine Y's can pack 12(64) or 768 crates in 1 hour.