SOLUTION: jackie's average mark on her 3 tests was 78.the makrk on test one was 86. her averge mark on the fist two was 3 more thn her mark on the third.what marks did she recieve on her sec

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Question 73366This question is from textbook it's a sheet
: jackie's average mark on her 3 tests was 78.the makrk on test one was 86. her averge mark on the fist two was 3 more thn her mark on the third.what marks did she recieve on her second and third test? This question is from textbook it's a sheet

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
%28x+%2B+y+%2B+z%29%2F3+=+78
%28x%2By%29%2F2+=+z+-+3
x+%2B+y+%2B+z+=+234
x+%2B+y+-+2z+=+-6
3z+=+240
z+=+80
x+=+86 (given)
86+%2B+y+%2B+80+=+234
y+=+234+-+166
y+=+68
The marks on the 2nd & 3rd test were 68 and 80
check
86+%2B+68+-+2%2A80+=+-6
154+-+160+=+-6
-6+=+-6
OK
86+%2B+68+%2B+80+=+234
234+=+234
OK