Question

A and b together can complete a work in 12 days. A alone can complete it in 20 days. If bdoes the work only for half a day daily, then in how many days a and b together will completethe work?

Answer 1

Ans: 15 days

Work done by A in 1 day
=
1
20
=
1
20

Work done by A and B in 1 day
=
1
12
=
1
12

Therefore, Work done by B in 1 day
=
1
12
−
1
20
=
1
30
=
1
12
−
1
20
=
1
30


Work done by B in half a day
=
1
60
=
1
60


Therefore, A's 1 day work + B's half day work
=
1
20
+
1
60
=
1
15
=
1
20
+
1
60
=
1
15


i.e., 15 days are needed.


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Answer 2

It would take 15 days to complete the work.

Step-by-step explanation:

Consider the provided information.

A and B  together can complete a work in 12 days. A alone can complete it in 20 days.

First find the LCM of 12 and 20.

12 = 2×2×3

20 = 2×2×5

LCM of 12 and 20 is 2×2×3×5=60

A and B  together can complete a work in 12 days.

If there are 60 units and A and B can make them in 12 days, that means they are making $\frac{60}{12}=5$ units per day.

A can make 60 units it in 20 days, that means A can make $\frac{60}{20} =3$ units per day.

Together they are making 5 units where A alone can make 3 units that means B alone can make 2 units per day.

In half day B can make 1 unit.

Total units made in 1 day if b does the work only for half a day daily, is 3+1=4.

Therefore, the number of days to complete the work is: $\frac{60}{4}=15$ days

Hence, it would take 15 days to complete the work.

#Learn more

A and B can do a given piece of work in 8 days B and C can do the same work in 12 days and a b c complete it in 6 days in how many days can A and C finish it​

https://brainly.in/question/11917539