Answer: 60°
Step-by-step explanation;
Sum of angles in a ∆=180°
We sum each of the angles and equate to 180°
(6x-40) + {180- (180-3x) }+ (X+20) =180
6x+3x+x-40+20=180°
10x-20=180°
10x=180+20
10x= 200° therefore, X=20
Substitution to solve <BAC
180-3x
180-3(20)
180-60
120
Applying angle in a straight line, we have
180-120
= 60°