If a 12-meter-tall airplane hangar casts a 18-meter shadow at the same time a parked jet casts a 6-meter shadow , how tall is the jet?

Given 
  12 meters tall airplane
  18 meter shadow of airplane
  6 meter shadow of jet
Find the measurement of the jet (y)
Solution
 6y = 12 + 18                         30
       >     y   =    >  y= 5
 6           6                              6

The answer is 5 meters tall is the measurement of a parked jet. 

Step-by-step explanation:

step 1

Find out the number of revolutions in one hour

we know that

The bicycle wheels are making 30 revolutions per minute

One hour are 60 minutes

so

using proportion

step 2

Find out how many feet the bicycle will travel in one hour

we know that

A bicycle moves approximately 7 feet with each revolution and the number of revolutions in one hour is 1,800

so

Multiply the number of revolutions in one hour (1,800 rev) by 7 feet