Percentages 64334

In the first delivery of 120 parts, there was 5% waste. In the second delivery in which, 10% of the 80 were scrapped. How much scrap was brought in with the first and second deliveries combined? What % of scrap was there in both deliveries of parts, out of the total number of parts brought? Round the result to whole percentages.

Correct answer:

n =  14
p =  7 %

Step-by-step explanation:

$$\begin{gathered} n_1=120 \\ {q}_1=5\%=\frac{5}{100}=\frac{1}{20}=0.05 \\ {n}_2=80 \\ {q}_2=10\%=\frac{10}{100}=\frac{1}{10}=0.1 \\ a=n_1\cdot q_1=120\cdot 0.05=6 \\ b=n_2\cdot q_2=80\cdot 0.1=8 \\ n=a+b=6+8=14 \end{gathered}$$

$p=100\cdot \frac{n}{n_1+n_2}=100\cdot \frac{14}{120+80}=7\%$

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