Question

A can finish a project in 10 days alone, B can finish the project in 15 days, and C can finish the project in 20 days. They work together for some time, then A is sick and leaves. The project is finished in 6 days. How many days are from the start when A leaves the project?

Answer 1

A, B, and C worked together for 13 days before A left the project.

Step-by-step explanation:

To find out how many days are from the start when A leaves the project, we need to calculate how many days it took for A, B, and C to complete a fraction of the project together. Let's assume the complete project is represented as 1.

So, the fraction completed by A, B, and C in one day is:

A: 1/10

B: 1/15

C: 1/20

When they worked together for a certain number of days, they completed a fraction of the project. Let's assume x is the number of days they worked together. So, the fraction completed by A, B, and C in x days is:

(1/10 + 1/15 + 1/20) * x

Given that the project was finished in 6 days, we can set up the equation:

(1/10 + 1/15 + 1/20) * 6 = 1

Simplifying the equation, we get:

(6/150 + 4/150 + 3/150) = 1

Therefore, they worked together for 13 days before A left the project.