If three identical cylinders weigh as much as five identical spheres, and three of these spheres weigh as much as twelve identical cubes, then how many cylinders weigh as much as sixty cubes?
3 Cylinders = 5 Spheres (1)
3 Spheres = 12 Cubes (2)
Multiply (2) by 5 on each side
60 Cubes = 15 Spheres (3)
Multiply (1) by 3 on each side
9 Cylinders = 15 Spheres (4)
So (3) and (4) imply that
9 Cylinders = 60 Cubes
3x=5y
3y=12z
15y=60z
9x=15y
9 cylinders