Question

Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 2 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 73?

Mark has how many marbles to sell?
Don has how many marbles to sell?
Show your work and explain how you arrived at your answers.

Answer 1

let’s label Mark’s marbles as ‘x’ and don’s as ‘y’.
so Don has 1 more than 2 times ‘x’.
This is written as:
y=2x+1

73 is the sum of ‘x’ and ‘y’, so x+y=73.

To solve for x, substitute our equation for y:
x+(2x+1)=73
Simplify:
3x=72
x=24

Now that we have x, solve for y:
y+24=73
y=49

Mark has to sell 24 marbles,
Don has to sell 49 marbles

Hope this was helpful!