Final answer:
A, B, and C will take approximately 2.2 days to complete the work together
Step-by-step explanation:
To find how long it will take A, B, and C to complete the work together, we can calculate their combined work rate per day.
A completes 1/20 of the work per day, B completes 1/5 of the work per day, and C completes the work in the same time as A and B combined. This means C also completes 1/20 + 1/5 = 1/4 of the work per day. Therefore, the combined work rate of A, B, and C is 1/20 + 1/5 + 1/4 = 9/20 of the work per day.
To find how many days it will take to complete the work, we can use the formula: time = 1 / (combined work rate).
Therefore, the time it will take A, B, and C to complete the work together is 1 / (9/20) = 20/9 ≈ 2.2 days.