Question

A can do a work in 15 days and B in 20 days. If they together work on it for 4 days, then the fraction of the work done is​

Answer 1

ANSWER::))

>>Take LCM of 15 and 20 as the total amount of work which is 60 units in this case.

>>A can do work in 15 days therefore amount of work done by A in 1 day is 60/15 = 4 units

>>B can do work in 15 days therefore amount of work done by A in 1 day is 60/20 = 3 units

>>Total amount of work done in 1 day =A work of 1 day+B's work of 1 day=4 units +3 units=7 units

>>Amount of work done in 4 days =4*7=28 units

>>Amount of Work Left = 60–28=32 units

>>Fraction of work left = Amount of work left/ >>Total Work = 32/60 = 8/15.

Step-by-step explanation:

hope it's help ✌️✌️

Answer 2

Answer:

A do a work in 15 days

so, A's 1 say work =1/15

B do a work in 20 days

so, B's 1 day work =1/20

(A+B)'s 1 day work= 1/15+1/20

= (4+3)/60

=7/60

its 4 day work= 7/60×4

=7/15

total work =1÷7/15

=1×15/7

= 15/7

= 2 1/7