Question

answer me this question

if 4/5 of a cistern is filled in 1 minute, how much time will be required to fill the empty cistern?


its answer is 1 min 15 sec

plz give me only its explanation.....that i understood properly....

Answer 1

Answer:

Step-by-step explanation:

let

cistern volume be x

and time taken for 4/5*x is 1min

time taken for x=5/4min

=1.25

time taken for filling or doing  empty is 1.25 not 1.15

Answer 2

Step-by-step explanation:

cistern volume be x

and time taken for 4/5*x is 1min

time taken for x=5/4min

=1.25

time taken for filling or doing empty is 1.25

not 115