Question

. Joseph and Peter can complete a work in 20 hours and 25 hours respectively.
Find : (i) work done by both together in 4 hrs.
(ii) work left after both worked together for 4 hrs.
(iii) time taken by Peter to complete the remaining work.​

Answer 1

Answer:

Joseph can do a work in 20 hours

Peter can do the same work in 25 hours

Now Joseph’s 1 hour’s work = 1/20

And Peter’s 1 hour’s work = 1/25

Both’s 1 hour’s work = 1/20 + 1/25

= (5 + 4)/100

= 9/100

(i) Both’s 4 hours work = 9/100 × 4 = 9/25

(ii) Work left = 1 – 9/25

= (25 – 9)/25

= 16/25

(iii) Peter can do 16/25 work in = 25 × 16/25

= 16 hours