We know that Luke lost x pounds the first week.
We also know that the second week 3/2 less than 3/2 times the pounds he lost the first week, this means that the secons week he lost:
Finally the third week he lost 1 pound more than 3/4 of the pounds he lost the first week. This can be written as:
Hence luke lost a total of:
Therefore the expression for Luke's weight loss is:
Liam lost the first week 1 pound less than 3/2 times the loss Luke had the first week this can be express as:
The second week he lost 4 pounds less than 5/2 times the loss of Luke the firs week then we have:
Finally Liam lost 1/2 pound more than 5/4 times the loss of Luke the first week, then:
Adding this we have:
Therefore Liam's expression is:
Now, we know that both of them lost the same weight, then we have the equation:
Solving for x we have:
Therefore Luke lost 2 pound the first week.
Finally we plug the value of x in the expression for Luke's weight loss to get the total amount over the three weeks:
Therefore they lost 6 pounds in three weeks.