Answer:
6 min
Explanation:
given that the rate for the first student is 10 min per wall
we can express this in wall per minute by taking the reciprocal
hence student 1's unit rate = 1/10 wall per min
similarly, we can express student 2's unit rate as 1/15 wall per min.
if we add up the two, we will get the amount of wall painted by two people working together per min
amount of wall painted per min by 2 people
= wall per min of person 1 + wall per min of person 2
= 1/10 + 1/15
= 3/30 + 2/30
= 5/30
= 1/6 wall per min.
to convert this to minutes per wall, we take the reciprocal:
number of minutes that both people will take to paint the wall
= 1 / (1/6)
= 6 min per wall (answer)