Answer:
A) 17.5%
B) 1) 2135 kg
2) 375 kg
C) 91.8
Explanation:
Part (A):
1 tonne= 1000 kg= 100%
Aluminium oxide= 825 kg= 82.5%
Iron (lll) oxide= 100 kg= 10%
Sand= 85 kg= 7.5%
That makes total of 100%
So, the percentage of impurities= Iron (lll) oxide + Sand
=> 10 + 7.5= 17.5%
Part (B):
(1) 1 tonne= 427 kg
Multiplying both sides by 5
=> 5 tonne= 427 * 5
=> 5 tonne = 2135 kg
(2) 1 tonne contains 75 kg sand as impurity
=> 1 tonne= 75 kg
Multiplying both sides by 5
=> 5 tonnes = 75 * 5
=> 5 tonnes = 375 kg
Part (C):
If all of the iron oxide was removed, then only aluminium and sand are left.
Aluminium = 825 kg
Sand= 74 kg
Total of them makes it:
=> 825 + 74 = 899
So,
% age of Aluminium= 825/899 * 100
% age of Aluminium= 0.918 * 100%
% age of Aluminium= 91.8%
