Question 909140
H + C = 269,000
H = 1.75C (which is doubtful unless the coal plant is very inefficient and the hydro plant is near Niagara or some other huge source, but that's for another day)
Substitute the value of H from the bottom equation into the top.
H + C = 269,000
1.75C + C = 269,000
2.75C = 269,000
Divide each side by 2.75
C = 97818.181818...
rounded to 97,818 people
H serves 1.75 * 97,818, or 171,182 people
Add together: 97818 + 17182 to get 269,000