A wheel that has 12 cogs is meshed with a larger wheel of 24 cogs. If the smaller wheel has made 44 revolutions, then find the number of revolutions made by the larger wheel.

Question: A wheel that has 12 cogs is meshed with a larger wheel of 24 cogs. If the smaller wheel has made 44 revolutions, then find the number of revolutions made by the larger wheel.

Solution:
As number of cogs increase, the revolutions made decrease. Hence, this is a problem related to indirect proportion.
Let the number of wheels be x.
More cogs (↑),Less revolutions (↓)

24 : 12 : : 44 : x
⇒ 24 × x = 12 × 44
⇒ x = (12 × 44)/24
∴ x = 22