Answer:
The angle B = 70°
Step-by-step explanation:
The sum of angles of a triangle is 180°
=> 40°+(2x-30)°+(x+20)° = 180°
=> 40°+2x°-30°+x°+20° = 180°
=> 30°+3x= 180°
=> 3x = 180°-30°
=> 3x = 150°
=> x = 150/3
=> x = 50°
So,the value of x = 50°
now , angle B = (2x-30) = (2×50 -30 ) = (100-30) = 70°
