bbb911
  • bbb911
Jaci averaged 84 on her first three history exams. The first score was 67. The second score was 7 less than the third score. What did she score on the second and third exams?
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
jim_thompson5910
  • jim_thompson5910
let x = score on second exam and y = score on third exam
bbb911
  • bbb911
so x would be 67
jim_thompson5910
  • jim_thompson5910
we know that "The second score was 7 less than the third score", so we can make this equation: x = y - 7

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

jim_thompson5910
  • jim_thompson5910
67 is the first exam score
jim_thompson5910
  • jim_thompson5910
the second may be 67, but we haven't gotten there yet
bbb911
  • bbb911
so would it be like this 67x=y-7
jim_thompson5910
  • jim_thompson5910
so we know this so far first exam score: 67 second exam score: x third exam score: y replace x with y-7 (since x = y-7) to get first exam score: 67 second exam score: y-7 third exam score: y
jim_thompson5910
  • jim_thompson5910
now you add up all 3 scores, then divide by 3 to get the average of 84 like this (Score1 + Score2 + Score3)/3 = Average (67 + (y-7) + y)/3 = 84 (67 + y-7 + y)/3 = 84 (2y+60)/3 = 84 2y+60 = 84*3 ... ... ... y = ???
bbb911
  • bbb911
oh ok so i use this equation right ?:)
jim_thompson5910
  • jim_thompson5910
yes
bbb911
  • bbb911
kk one sec
jim_thompson5910
  • jim_thompson5910
ok
bbb911
  • bbb911
so you don't have to divide the 3?
jim_thompson5910
  • jim_thompson5910
what do you mean
bbb911
  • bbb911
(2y+60)/3 = 84 2y+60 = 84*3 like here how instead of dividing you multiplied 3 to 84
jim_thompson5910
  • jim_thompson5910
oh i multiplied both sides by 3 because in the end you want to isolate y
jim_thompson5910
  • jim_thompson5910
so you undo that division by 3
bbb911
  • bbb911
oh ok :) thnks one moment
jim_thompson5910
  • jim_thompson5910
ok
bbb911
  • bbb911
is it 96 ?
jim_thompson5910
  • jim_thompson5910
yep, y = 96 now find x
bbb911
  • bbb911
okay now do you plug in the y to the very first equation you gave me?
jim_thompson5910
  • jim_thompson5910
yep x = y - 7
bbb911
  • bbb911
is it 89
jim_thompson5910
  • jim_thompson5910
yep x = 89 y = 96
bbb911
  • bbb911
yesss! thank you so mcuh :)
jim_thompson5910
  • jim_thompson5910
so going back to what we defined x and y to be (remember at the top we said "let x = score on second exam and y = score on third exam", so you can see how it all comes around full circle) we know first exam score = 67 (given) second exam score = 89 (just found) third exam score = 96 (just found)
jim_thompson5910
  • jim_thompson5910
yw

Looking for something else?

Not the answer you are looking for? Search for more explanations.