Question

In a shipment of $120$ machine parts $5$ percent were defective In a shipment of $80$ machine parts $10$ percent were defective. For the two shipments combined what percent of the machine parts were defective?

• A. $6.5\%$
• B. $7.0\%$
• C. $7.5\%$
• D. $8.0\%$

Answer 1

The correct option is B $7.0\%$

Defective parts in the shipment of $120$
$=5\%$ of $120$ $=\frac{5}{100}\times 120=6$
Defective part in the shipment of $80=10\%$ of $80$
$=\frac{10}{100}\times 80=8$
$\therefore$ Total machine parts $=120+80=200$
Total defective parts $=6+8=14$
% of defective parts $=(\frac{14}{200}\times 100)$ $=$ $7\%$