A global gym decides to replace all of its cardio machines.  They have 20 gyms.  Each gym has 10 bikes, 5 treadmills, and 5 elliptical machines.  The bikes cost $700 each.  The treadmills cost 50% more than that.  The elliptical machines are twice as expensive as the treadmills.  How much does it cost to replace everything?
Give me a clear explanation.