SOLUTION: 3. Ginger over the course of an average work-week wanted to see how much she spent on lunch daily. On Monday and Thursday, she spent $5.43 total. On Tuesday and Wednesday, she spen

Question 284710: 3. Ginger over the course of an average work-week wanted to see how much she spent on lunch daily. On Monday and Thursday, she spent $5.43 total. On Tuesday and Wednesday, she spent $3.54 on each day. On Friday, she spent $7.89 on lunch. What was her average daily cost?
answer: $4.08
-------------------------------------------------------------------------------
This question is from a practice placement test for SMC. here is the url
http://www.testprepreview.com/modules/averagesandrounding.htm
Taking the average of an average is already confusing but this problem goes beyond that. I tried using matrixes but it wont work since we have two equations but three variables. (the equations being derived from the meaning of average--such as adding two days and dividing by two)I also tried trial and error but it still did not work.
thank you for your time
Answer by edjones(8007) (Show Source): You can put this solution on YOUR website!
5.43
3.54
3.54
7.89
-----add
20.40
.
20.40/5 = 4.08
.
Ed
RELATED QUESTIONS
1.The average daily number of persons passing a certain point on sunday,monday,friday and (answered by Cromlix)

Sarah had a test on Thursday. She studied for the test for 2/3 of an hour on Monday, 3/4... (answered by rvfer)

Janice ran 5.6km every day from Monday to Wednesday for cross country training. On... (answered by josgarithmetic)

The amount that mary drives changes from week to week, so the amount that she spends on... (answered by funmath)

Updated questions with added information: A specific study found that the average... (answered by ikleyn)

Shelby goes to the craft show. She spends half of the money she brought with her on a toy (answered by solver91311)

Last weekend, I was given my allowance, which is meant to last me all week. On Monday, I (answered by richwmiller)

She had $12. She bought 3 pens at $4g and spent $3g on lunch. How much had she... (answered by Alan3354)

robin ate some peanuts on sunday on Monday she ate 2 more peanuts than sunday on Tuesday... (answered by greenestamps)