Question

plz answer this question step by step...

Answer 1

35 minutes is the answer

Answer 2

Hello here is your answer by Sujeet yaduvanshi ☝☝☝☝☝☝☝☝



Question:-) Angela takes 40 minutes to dust and clean her home while her sister rani takes an hour (6o min) to do same work. One day their mother joins the two sisters and together the three of them dust and clean their house in just 15 min. How long would their mother take if she did the job alone. 



Answer:-)Let to be time x


then,


Following the question as per as
$\: \: 15(1/40 + 1/60 + 1/x) = 1 multiplying both sides by 2400x: 15(60x + 40x + 2400) = 2400x 15(100x + 2400) = 2400x 1500x + 36000 = 2400x 36000 = 900x 40 = x \\ x = 40$