Question 827135
these look to be set up alor like age word problems more than quadratics.

tank A and tank B

"Two tanks contain equal amounts of water." {{{A=B}}}
so if we take 3000 liters from {{{A}}} and give it to {{{B}}} they are now saying that {{{B}}} has 6 times more water than {{{A}}}
its the same as saying {{{A-3000}}} is now 1/6 of {{{B+3000}}}
the equation will look like:
{{{A-3000=(B+3000)/6}}}
now if A=B sub out A with B
{{{B-3000=(B+3000)/6}}}
get rid of fraction by multiplying by 6
{{{6B-18000=B+3000}}}
subtract a B and add 18000 to both sides
{{{5B=21000}}}
divide by 5
{{{B=4200}}}
so if {{{A=B}}}
then {{{A=highlight(4200)}}}
now check
if 3000 gets taken from A and given to B it should look like this
{{{4200-3000=1200}}}=the new value for A and {{{4200+3000=7200}}}= the new value for B
B should be 6 times greater lets see
{{{7200/1200=6}}}
this is correct

whoops forgot the second equation....


1 page has P amount of lines

there is 120 pages in the book so 120P=total amount of lines in the book
so if P is reduced by 3 the book would need 20 more pages to be equal to original set up.
{{{120P=140(P-3)}}} I added the 20 pages to the original 120 pages and that total like the first part gets multiplied by how many lines there are per page.
(total pages times lines per page)=(total pages times lines per page)
distribute the 140
{{{120P=140P-420}}}
subtract 120P and add 420 to both sides
{{{420=20P}}}
divide by 20
{{{highlight(21)=P}}}
so this means that originally there were 21 lines per page
lets check to make sure
{{{120(21)=2520}}}lines in book
{{{140(21-3)=2520}}}lines in book
this is correct