Question

An electrician can wire a house in 20 hours. if she works with an apprentice, the same job can be completed in 12 hours. how long would it take the apprentice, working alone, to wire the house?

Answer 1

It would take the apprentice 30 hours to wire the house alone.

Step-by-step explanation:

Let's assume that the work done by the electrician alone in 1 hour is represented by E, and the work done by the apprentice alone in 1 hour is represented by A. According to the given information, the electrician can wire the house in 20 hours, so E = 1/20. When the electrician and the apprentice work together, they can wire the house in 12 hours, so their combined work in 1 hour is represented by (E + A) = 1/12.

To find out how long it would take the apprentice to wire the house alone, we can subtract the work done by the electrician in 1 hour (E) from the combined work done by both the electrician and the apprentice in 1 hour (E + A), which gives us A = (E + A) - E. Substitute the values:

A = (1/12) - (1/20) = (20 - 12) / (12 x 20) = 8 / 240 = 1/30.

So, the apprentice can wire the house alone in 30 hours.