In one alloy there is 12% chromium while in another alloy it is 8%. 10 kg of the first alloy was melted together with 30 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy.  Choose one:
A) 9.4%
B) 9.6%
C) 9%
D) 9.8%
E) 10%
The amount of chromium in the new 10+30= 
<gadget id="calculator">10+30</gadget>
<output>40</output>
40 kg alloy is  0.12*10+0.08*30= 
<gadget id="calculator"> 0.12*10+0.08*30</gadget>
<output>3.6</output>
3.6 kg, so the percentage is  3.6/40*100= 
<gadget id="calculator"> 3.6/40*100</gadget>
<output>9</output>
9%.   Answer: 9%
<result>C</result>
In one alloy there is 12% chromium while in another alloy it is 8%. 10 kg of the first alloy was melted together with 30 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy.