Medal
How many kilograms of nickel silver containing 16% zinc and how many kilograms of nickel silver containing 31% zinc must be melted together to produce 711 kg of a new nickel silver containing 24% zinc?

Treat the percents given in this exercise as exact numbers, and work to three significant digits.

? kg of 16% alloy and
? kg of 31% alloy

Question

Medal
How many kilograms of nickel silver containing 16% zinc and how many kilograms of nickel silver containing 31% zinc must be melted together to produce 711 kg of a new nickel silver containing 24% zinc?

Treat the percents given in this exercise as exact numbers, and work to three significant digits.


? kg of 16% alloy and 
? kg of 31% alloy

anonymous · Answer

@campbell_st  can you please help me

anonymous · Answer

we need a variable, lets say $x$ is the number of kg of 31% zink

anonymous · Answer

since the total is $711$ the amount of 21% zink must therefore be $711-x$

anonymous · Answer

16% i meant

anonymous · Answer

then $x$ kilos of 31% zink has $.31x$ zink in it. and similarly the $711-x$ kilos of 16% zink has $.16(711-x)$ kilos of zinkk

anonymous · Answer

you want $711\times .24=170.64$ kilos of zink 
set $$.31x+.16(711-x)=170.64$$ and solve for $x$

anonymous · Answer

easier to solve by removing annoying decimals and solve$$31x+16(711-x)=17064$$

anonymous · Answer

31x+11376-16x=17064

anonymous · Answer

x=379.2

anonymous · Answer

am I right @satellite73