I think first 80 and second 90
Answer:
58.33 lbs.
Step-by-step explanation:
There are already 25 lbs of alloy of copper
Of this 25 lbs, 20% is pure i.e. copper content = 25(0.5) = 5lbs.
Now available is
Copper Other metals
5 lbs 20 lbs
Let x lb of 30% copper is added.
Then new alloy will have 5+0.3x lb copper in total of 25+x lbs
Percentage pure = 
Simplify to get

Hence answer is 58.33 lbs should be added.
Answer:
Wrong
Step-by-step explanation:
The student is wrong. Two angles are coterminal if and only if the difference between their measures is a multiple of 360°.
The difference between the angles 180° and –180° is 360°, and they are coterminal. Therefore the student is WRONG.