1) in one minute for first wiil be 1/20
the other 1/30, it means that A paint in one minute 1/20 and B 1/30 then A+B in one minute 1/20 + 1/30 = 3+2/60 = 5 / 60, 5/60 = 1/12
if in one min they make 1/12 then in 12 min they paint all the wall
Answer:
9
Step-by-step explanation:
Step-by-step explanation: A line, ray, or line segment (referred to as segment) that is perpendicular to a given segment at its midpoint is called a perpendicular bisector. ... In the diagram above, RS is the perpendicular bisector of PQ, since RS is perpendicular to PQ and PS≅QS. Additionally, since PS≅QS, point S is the midpoint of PQ.