Unemployment and Labor Force MacroEconomics Suppose that the total population on the 1st of January 2001 was 40 million people, of which 30 million were above age 16. Suppose that among the latter, 12 million people were not working or actively looking for work, and 2 million were unemployed. 800,000 people are expected to turn 16 during 2001 and half of them are expected to keep studying and not to seek a job, while the other half is expected to seek a job and be ready to start working immediately. How many people have to find a job during 2001 for the unemployment rate to be 8 %.
A short note: please try to show your math work in the original post, and maybe learn some basic Math TeX commands. It makes people much more willing to help with homework questions.

So first, we have our unemployment for the year 2000. Let $U_t, u_t, L_t$ denote the unemployment rate, number of unemployed, and number of laborers at time $t$, respectively.

$$U_t = \frac {u_t}{u_t + L_t}$$
$$U_{2000} = \frac {2,000,000}{2,000,000 + 16,000,000} = \frac{1}{9} \approx 0.111$$

So in the year 2001, 800,000 people turn 16, but half do not enter the labor force. So the question is how many people have to find a job for unemployment to fall below 8%.

$$U_{2001} = \frac{2,000,000 + (400,000 - n)}{2,000,000 + (400,000 - n) + 16,000,000 + n} = 0.08$$

where $n$ is the number of those who found jobs, and $400,000 - n$ is the net change in unemployment numbers. Solve for $n$.

$$\frac{2,400,000 - n}{18,400,000} = 0.08$$
$$\implies 1,472,000 = 2,400,000 - n \implies 928,000 = n$$

So what does this tell us? Even if all 400,000 new 16 year olds found jobs, that would not drive unemployment down to 8%. You need quite a few more people to find jobs.