Question by Lê Quốc Trần Anh

11/01/2018 at 17:14

Phan Thanh Tinh Coordinator 12/01/2018 at 22:08

In 1 minute, they can do \(\dfrac{1}{30}\) of the job together and Gertrude can do \(\dfrac{1}{40}\) of the job alone, so Bertha can do : \(\dfrac{1}{30}-\dfrac{1}{40}=\dfrac{1}{120}\) of the job alone

The answer is : 120 minutes = 2 hours
Lê Quốc Trần Anh selected this answer.
FA Liên Quân Garena 13/01/2018 at 21:15

In 1 minute, they can do 130130 of the job together and Gertrude can do 140140 of the job alone, so Bertha can do : 130−140=1120130−140=1120 of the job alone

The answer is : 120 minutes = 2 hours