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$?$

Answer 1

Step $1:$ Find the total number of defective parts.

Since, $5\%$ parts are defective in a shipment of $120$ machines.

$\frac{5}{100}·120=6$

Therefore, $6$ parts are defective in a shipment of $120$ machines.

Since, $10\%$ parts are defective in a shipment of $80$ machines.

$\frac{10}{100}·80=8$

Therefore, $8$ parts are defective in a shipment of $80$ machines.

Step $2:$ Compute the required percentage.

The total number of machine parts shipped will be given by:

$120+80=200$

The total number of defective parts will be given by:

$6+8=14$

So, the percentage of defective parts in the two shipments combined is:

$\frac{14}{200}·100=7\%$

Hence, $7\%$ parts are defective in the two shipments combined.