Question

. What was the percentage of lead in the original ore sample?

Answer 1

Answer:
There is not mass of original ore sample, therefore we can choose mass= A g
If B g lead in the original ore sample, we can find percentage of lead:
W%Pb = (B x 100 %) / A
If
A = 100 g
B = 21 g
W%Pb = (21 x 100%) / 100
W%Pb = 21%