a Does the percent of working teenagers increase or decrease?
B
b Use the given percent of teenagers with a summer job.
A
a Decreased, see solution.
B
b ≈ 361
Practice makes perfect
a We are given the percent of American teenagers that had summer jobs in June 2000 and 2006. To determine if the number of teenagers with summer jobs increased or decreased since 2000 we should compare the given percents.
The percent of teenag&ers having summer job
June2000 & June2006
60.2 % & 51.6 %
Since 51.6 % is less than 60.2 % the number of teenagers with summer jobs decreased. Notice that we assume that the number of teenagers did not change during this time.
Alternative Solution
What would happen if the number of teenagers changed?
In our solution we assumed that the number of teens did not change. However, this could be not a realistic assumption. Let's see what would happen if the number of teens changed. First, let's assume that there were 2 million teens 16 to 19 years old in June 2000.
60.2 %*2 000 000=1 204 000
This means that 1 204 000 of teenagers had summer job. Next, let's assume that the number of teens 16 to 19 years old increased to 2.5 million in June 2006.
51.6 %*2 500 000=1 290 000
As we can see, despite the fact that 51.6 % is less than 60.2 %, the number of teenagers with summer jobs increased. 51.6 %&< 60.2 %
1 290 000&>1 204 000
Therefore, the information about the total number of teenagers in each year is necessary to determine whether the number of teens with summer jobs increased or decreased.
b Since we are given that in June 2006 51.6 % of teens had summer jobs, we will multiply this percent by 700.
