8. What is the difference between $40 \%$ of $50 \%$ of 60 and $50 \%$ of $60 \%$ of 70 ?
A 9
B 8
C 7
D 6
E 5
8. A $40 \%$ of $50 \%$ of 60 equals $40 \%$ of $30=12$. Also, $50 \%$ of $60 \%$ of 70 is $50 \%$ of $42=21$. So the required difference is $21-12=9$.