5. What is $10 \%$ of $30 \%$ of $50 \%$ of 7000 ?
A 15
B 105
C 150
D 501
E 510
5. B The calculation is equivalent to $\frac{1}{10} \times \frac{3}{10} \times \frac{5}{10} \times 7000=1 \times 3 \times 5 \times 7=105$.