Respuesta :

t + f = 12

25t + 65f = 420

Solve for t

t = 12 - f

25(12 - f) + 65f = 420

300 - 25f + 65f = 420

40f = 420 - 300

40f = 120

f = 120/40

f = 3

Find t

t = 12 - 3

t = 9

So, f = 3 and t = 9