99.5k views
5 votes
one student can paint a wall in 10 minutes another student can paint the same wall in 15 minutes working together how long will it take for them to paint the wall?

User Spoonface
by
7.5k points

1 Answer

3 votes

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)

User KrekkieD
by
6.9k points