Andy, david and tim altogether have 180 stamps. andy has 20 fewer than david, and tim has 80% of the sum of andy's and david's stamps. how many stamps does each of them have?

Step-by-step explanation:

Alright, lets get started.

Let Andy have A stamps.

Let David have D stamps.

Let Tim have T stamps.

Andy, David and Tim altogether have 180 stamps, means

Andy has 20 fewer than David, means

Tim has 80% of the sum of Andy's and David's stamps, means

Putting the value of D as A+20 in equation 1 and 3

........................equation 5

.......   equation 6

Plugging the value of T in equation 5

It means Andy has 40 stamps.

It means David has 60 stamps.

It means Tim has 80 stamps.

Hope it will help :)

you didn't give me the choices, so i will just give you the graph so you can look at your choices and choose the right one.