Question

Mike, an experienced bricklayer, can build a wall in 3 hours, while his son, who is learning, can do the job in 6 hours. How long does it take for them to build a wall together?

Answer 1

• 2 hours

Explanation:

Mike's speed:

• 1/3 wall in an hour

Son's speed:

• 1/6 wall in an hour

Speed of both together:

• 1/3 + 1/6 =
• 2/6 + 1/6 =
• 3/6 = 1/2

They can build 1/2 wall in an hour

or

Build a wall in 2 hours