OFFICIAL SOLUTION


5,490

Here we need both the graph and the pie chart. We can find the number of domestic industrial ship inspections in 1970 by the combination of the two, then we can use the information in the question stem to extrapolate to the number for 1972. The answer choices are pretty close together again, so we should be careful with our estimations. In 1970, 25 percent or $\frac{1}{4}$ of the domesticship inspections were industrial ships. We learn that from the pie chart. In 1970, the total number of domestic-ship inspections was about 13 thousand. We know that from the bar graph. Putting the two pieces of information together, we see that approximately $\(\frac{1}{4}\)$ of 13 thousand or about 3,250 domestic industrial ships were inspected in 1970. Then in 1971, 30 percent more domestic industrial ships were inspected than in 1970. 30 percent of 3,250 is the same as $3 \times 325$ or 975. So the increase from 1970 to 1971 was 975 ships. This makes the 1971 total $3,250+975$ or 4,225 ships. Then in 1972 it increased by 30 percent. Now what's 30 percent of 4,225 ? Well, $30 \%$ of 4,000 is $\(\frac{3}{10}\)$ of 4,000 or $1,200.30 \%$ of 225 is a little more than $30 \%$ of 200 which is 60 . So $30 \%$ of 4,225 is a little more than $1,200+60$ or 1,260 . So in 1972, a little more than $4,225+1,260$ or 5,485 ships were inspected.