Question

a an do a piece of work in 30 days while b alone can do it in 40 days. in how many days can a and b working together do it?

Answer 1

in this problem

lcm is work

30 , 40 lcm = 120 unit work

one days work of each i
120/30 = 4 unit

and

120/40 = 3 unit

they together one days work is

4 + 3 = 7 unit

120/7 = 17.14 days

Answer 2

Answer:

let the work be lcm

Step-by-step explanation:

then

30,40 = 120 unit work

one day work of each =

120/30= 4 units

AND

work done by B

= 120/40 = 3 units

they together do work in one day = 4+3

= 7 units

No. of days they take to do work = 120/7

= 17.14 days