Monday, September 25, 2006

Pretest 2: Question 2

2. The mean mark on 4 tests is 78%. What mark is needed on the next test to increase the mean to 80%?

average of 4 test is 78%

4 x 78 = 312 or 78 + 78 + 78 + 78 = 312 = sum of all data

average of 5 test is 80%

5 x 80 = 400 or 78 + 78 + 78 + 78 + ? = 400 =sum of all data

the difference between the both is

400 - 312 = 88

meaning 78 + 78 + 78 + 78 + 88 = 400



^_^
at

2 comments:

  1. Mr. H9/25/2006 7:32 PM

    check your math you are close but not quite there. Where do the sum of all datas come into play??

    Edit for perfection.

    Harbeck

    ReplyDelete
  2. Mr. H9/27/2006 6:15 PM

    Congrats on editing.

    HArbeck

    ReplyDelete

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