answer for this question?

Question

A can do a piece of work in 20 days while B alone can do it in 30 days. In how many days can A&B working together do it?

Answer 1

A does 1/20 of the job per day
B does 1/30 of the job per day.

Together, they do 1/20 + 1/30 = 5/60 = 1/12 job per day.

So, it will take them 12 days together.

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Answer 2

A and B will take 12 days to complete it.
To calculate such questions follow:
A's 1 day's work = 1/20 [i.e. A will do 1/20th work in 1 day]
B's 1 day's work =1/30 [B will 1/30th work in 1 day]
A and B's 1 day's work = 1/20 +1/30
= 1/12.

therefore A and B will do 1/12th of the work in 1 day.
This implies that both will do the work in 12 days.

Answer 3

Hint:

This is yet another way to look at this problem.

When A has finished the work, B will still have10 days remaining to finish the work.

But in those ten days A will finish 1/2 the work. If he start the work.

so in 30 days 2 and a 1/2 work is completed by A+B

So if they were to do it together then it will take 30day/ 2.5 = 12 days.

So. answer is 12 days.

Answer 4

12

Answer 5

The answer is 12 days.

Mathematically graphing them. It is one object, thus giving "it" a value of one.

So now that we know "it" is one then we can say....

Y = 1 - ((1/30)X)
Y = (1/20)X

find the location at which both linear function intersects and thats how many days it will take both A and B to do "it"

The answer is 12.

Answer 6

1/20+1/30=5/60
60/5=12 days

Answer 7

1/20x + 1/30x = 1

Multiply both sides of the equation by 60

60(1/20x) + 60(1/30x) = 60(1)

3x + 2x = 60

Collect like terms

5x = 60

Divide both sides of the equation by 5

5x / 5 = 60 / 5

x = 60/ 5

x = 12. . .←. .amount of days
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The work can be accomplihed in 12 days, with A & B working together.

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Answer 8

take the reciprocals of 20 and 30 and add then take that reciprocal and simplify to the correct answer 12

Answer 9

50

Answer 10

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