Respuesta :

x = # of hours tutoring ES
y = # of hours tutoring HS

equations
20x + 30y = 140
x + y = 6

solve
20x + 30y = 140
x + y = 6

x = 6 - y

substitute x = 6 - y into 20x + 30y = 140

20x + 30y = 140
20(6 - y) + 30y = 140
120 - 20y + 30y = 140
10y = 20
    y = 2

x = 6 - y
x = 6 -2
x = 4

answer
Tutor:
ES = 4 hours and HS = 2 hours