math exercises

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A workman makes U$ 4000,00 each 16 days of hard work; how much money is he going to make working hard 20 days?

 


A small spur gear with 30 teeth drives another gear with 25 teeth. When the first gear has made 450 revolutions, how many revolutions has the second one made?

 


A tap can fill a tank in 16 hours. How much time is needed for five identical taps to fill the same tank?

 


A machine working 6 hours each day produces 3000 hair clips in 5 days. How many hair clips will be produced if the machine is working 4 hours each day during 8 days?