Hi
I came across this problem in a high school text book. Appreciate if someone can explain the solution.
Q: What quantites of silver 60% and 82% pur must be mixed together to give 12 ounces of silver 70% pure.
A: x= no.of ounces of 60% silver
y= no.of ounces of 82% silver
x + y =12
(0.6)x+(0.82)y = (0.7)12
Solving the above 2 eqtn.s, x= 72/11 & y= 60/11
My question is why use 2 unknowns x & y? I had tried to solve it with just one unknown as follows:
(0.6)x + (0.82) (12-x) = (0.7)12
Solving the above eqtn., my answer was x = 6
It would be helpful if someone can explain.
Thanks
Pavithra
I came across this problem in a high school text book. Appreciate if someone can explain the solution.
Q: What quantites of silver 60% and 82% pur must be mixed together to give 12 ounces of silver 70% pure.
A: x= no.of ounces of 60% silver
y= no.of ounces of 82% silver
x + y =12
(0.6)x+(0.82)y = (0.7)12
Solving the above 2 eqtn.s, x= 72/11 & y= 60/11
My question is why use 2 unknowns x & y? I had tried to solve it with just one unknown as follows:
(0.6)x + (0.82) (12-x) = (0.7)12
Solving the above eqtn., my answer was x = 6
It would be helpful if someone can explain.
Thanks
Pavithra
