Two machines, Y and Z, work at constant rates producing identical items. Machine Y produces 5 items in the same time Machine Z produces 2 items. If machine Y takes 9 minutes to produce a batch of items, how many minutes does it take for machine Z to produce the same number of items?	Choose one: A) 6 B) 9 C) 9 1/2 D) 22.5 E) 13 1/2
rate z/rate y=2/5   time z/time y=5/2   5/2*9= 
<gadget id="calculator">5/2*9</gadget>
<output>45/2 = around 22.5</output>
22.5 minutes   22.5
<result>D</result>
Two machines, Y and Z, work at constant rates producing identical items. Machine Y produces 5 items in the same time Machine Z produces 2 items. If machine Y takes 9 minutes to produce a batch of items, how many minutes does it take for machine Z to produce the same number of items?