An ore contains 8% copper.How many kilograms of the ore are required to get 68kg of copper?
(a)544 kg
(b)5.44 kg
(c)85 kg
(d)850 kg.
68 kg is 8% of what?
(a)544 kg
(b)5.44 kg <== Get rid of this one immediately. Way too small.
(c)85 kg
(d)850 kg.
(a)544 kg
(c)85 kg <== Throw this one out. It's barely greater than 68 kg
(d)850 kg.
(a)544 kg <== Discard this one. 10% is 54.4 kg 8% is less.
(d)850 kg.
(d)850 kg. <== Only one left. 850 kg * 8% = 850 kg * 0.08 = 68 kg -- Perfect.
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Percentage-Decimal-Fraction Relations