Thread: How Many Yards Did Amy Use?

Mary and Amy had a total of 20 yards of material from which to make costumes. Mary used three times more material to make her costume than Amy used, and 2 yards of material was not used. How many yards of material did Amy use for her costume?

MY SET UP:

Let M = Mary

Let A = Amy

M + A = 20 yards
3M + A = 18 yards

I equated 3m + A to 18 because the question stated that 2 yards were not used.

Is this the correct group of equations or is the entire set up wrong?

Originally Posted by magentarita

Mary and Amy had a total of 20 yards of material from which to make costumes. Mary used three times more material to make her costume than Amy used, and 2 yards of material was not used. How many yards of material did Amy use for her costume?

MY SET UP:

Let M = Mary

Let A = Amy

M + A = 20 yards
3M + A = 18 yards

I equated 3m + A to 18 because the question stated that 2 yards were not used.

Is this the correct group of equations or is the entire set up wrong?

a valiant effort, but not really.

we only used 18 yards. so if M is the amount Mary used and A is the amount Amy used, then we have

M + A = 18 ..................(1)

if Mary used 3 times as much as Amy, it means M = 3A

thus 3A + A = 18

etc etc etc

Creating proper equations for given word problems is the main difference between students of math and math professionals like the tutors on this site. I have not been able to set up the right equations for questions since I started pre-calculus (and before this course). The course has two more semesters because we started in August.