Question

a takes to do complete a job in 15 days and b takes to do the same job in 20 day. if they work together,how many days to complete the job?​

Answer 1

$\frac{1}{15} + \frac{1}{20} \\ \frac{4 + 3}{60 } \\ \frac{7}{60} \\ .11$

Answer 2

Step-by-step explanation:

Let x be total work,

therefore a takes 15 days to complete a work

which is 1/15 of x per day and b = 1/20 of x

1/15×x +1/20× x = 1 (here 1 is job to do..)

x + x =1

15 20

3x + 4x = 1

60

7x = 60

x = 60/7 = 8.571 days