Question

sai and joseph can complete a work in 12 and 15 days respectively sai started the work and left the work after 4days. in order to complete the remaining work, how many days will joseph take?​

Answer 1

Suppose A and B do the work in x and y days respectively Now work done by A in 2 days + work done by B in 9 days = 1

⇒

x

2

+

y

9

=1 Similarly

x

3

+

y

6

=1 Let

x

1

=a and

y

3

=b Then the equations become

2a + 9b = 1 .......(i)

3a + 6b = 1 .......(ii)

Performing (ii) x 2 - (i) x 3 we get (6a + 12b) - (6a + 27b) = 2 - 3

⇒−15b=−1⇒b=

15

1

⇒x=15 ∴ Putting the value of b in (i)

2a+9×

15

1

=1⇒2a=1−

5

3

=

5

2

⇒a=

5

1

⇒y=5