Answer:
Mean time and 13
Explanation:
Since in the given question it is mentioned that there is a five people and they spend the work in 7,10,13,20,15 hours respectively
So here the concept i.e. used is average time or the mean time
And, this can be calculated below:
= Sum of observations ÷ number of observations
= (7 + 10 + 13 + 20 + 15) ÷ 5
= 13