Question 72308
3. In a recent year, the best selling DVD was the Lord of the Rings: The Fellowship of the Rings. Another big seller was Harry Potter and the Sorcerer's Stone, which sold 90 million less than the Lord of the Rings. If the two movies totaled 424 million, how many DVD's of each were sold?
1)Mexico = M
Red Sea = R
  M = 3R
   M -R = 1078
  replace 3R for M in second equation;
3R - R = 1078
2R = 1078
R=539
Now plug what you got for  in the second equation;
M - 539 = 1078
M = 1078 + 539
M = 1617
2)Ebay = E
Amazon = A
E = 2A-.1
E + A = 5.6
Replace 2A - .1 for E in second equation;
2A - .1 + A = 5.6
3A = 5.6 + .1
3A = 5.7
A = 1.9
Now plug that in for A in second equation;
E + 1.9 = 5.6
E = 5.6 - 1.9
E = 3.7
3)L = Lord of the rings
 S = Sorcerer's Stone
L + S = 424
S = L - 90
replace L - 90 for S in first equation;
L + L -90 = 424
2L = 424 + 90
2L = 514
L = 257
Now plug that in the first equation:
257 + s = 424
S = 424 - 257
S = 167
:)