Answer:
There were 333 seniors in 1990
153 seniors had jobs in 2010.
Step-by-step explanation:
Let the number of high school seniors in 1990 = x
75% of x had jobs in 1990
In 2010 there were 50 more seniors. That is, the number of seniors is x+50.
40% of (x+50) had jobs in 2010.
Total number of jobs in both years = 403.
\[0.75 * x + 0.4 * (x + 50) = 403\]
\[0.75 * x + 0.4 * x + 20 = 403\]
=> \[1.15 * x = 403 - 20\]
=> \[1.15 * x = 383\]
=> \[x = 383/1.15\]
=> \[x = 333\]
Number of seniors having job in 2010 = 0.4 * (333 + 50) = 0.4 * 383 = 153.2 = 153(approx)
