Respuesta :
Step-by-step explanation:
i)Initial School population,
given 15 units = 1200
1 unit =
[tex]1200 \div 15 \\ = 80[/tex]
Number of teachers (initial) = 1 unit = 80.
ii)take j = number of teachers joining the school.
New teacher population = 80+j
[tex] \frac{3}{43} (1280 + j) = 80 + j \\ \frac{3840}{43} + \frac{3}{43} j = 80 + j \\ j - \frac{3}{43} j = \frac{3840}{43} - 80 \\ \frac{40}{43} j = \frac{400}{43} \\ 40j = 400 \\ j = 400 \div 40 \\ = 10[/tex]