Question

Two printing presses, working together, can complete a job in 2 hours. If one press
requires 6 hours to do the job alone, how many hours would the second press need to
complete the job alone?

Answer 1

Ответ:

Working together, the two printing presses can complete the job in 2 hours, so their combined work rate is 1/2 of the job per hour.

The first press alone can complete the job in 6 hours, so its work rate is 1/6 of the job per hour.

The second press alone can complete the job in x hours, so its work rate is 1/x of the job per hour.

Now, we can set up an equation based on the combined work rate:

1/6 + 1/x = 1/2

To solve for x, we can multiply both sides of the equation by 6x (the least common multiple of 6 and x) to clear the fractions:

x + 6 = 3x

Now, subtract x from both sides:

6 = 2x

Finally, divide by 2 to solve for x:

x = 6/2

x = 3

So, the second press would need 3 hours to complete the job alone