It takes 2 tons of copper ore and 4 tons of iron ore to make one ton of alloy A. How many tons of alloy A can be made from 60 tons of copper ore and 90 tons of iron ore?  Choose the correct choice from the following options:	A) 18	B) 18 3/4	C) 20	D) 22 1/2	E) 50
Yes, you need copper ore:iron ore in the ratio 2:4. Total 6 tons of the mix in this ratio will give 1 ton of alloy A.   If you have 60 tons of copper ore, it is enough for 60/2= 
<gadget id="calculator">60/2</gadget>
<output>30</output>
30 tons of alloy A.   If you have 90 tons of iron ore, it is enough for 90/4= 22 1/2 tons of alloy A.   Since iron ore is available for only 22 1/2 tons of alloy A, you can make only 22 1/2 tons of alloy A.   The leftover copper ore alone cannot make any alloy A and hence will be leftover only.   Answer must be 22 1/2.   (22 1/2)
<result>D</result>
It takes 2 tons of copper ore and 4 tons of iron ore to make one ton of alloy A. How many tons of alloy A can be made from 60 tons of copper ore and 90 tons of iron ore?