Question 151789
Let us see the situations:
1st customer:
5MP+8HP=$840 ----------------> eqn 1
2nd customer:
3MP+4HP=$480 ----------------> eqn 2
In eqn 2 we get, {{{HP=(480-3MP)/4}}} and substitute in eqn 1:
{{{5MP+cross(8)2(480-3MP)/cross(4)=840}}}
{{{5MP+960-6MP=840}}}
{{{960-840=6MP-5MP}}}
{{{MP=120}}} ----------------------> cost of an MP3 player
For Head phones set, go back eqn 2:
{{{3*120+4HP=480}}}
{{{HP=(480-360)/4}}}
{{{HP=30}}}
In doubt? Go back eqn 1:
{{{5(120)+8(30)=840}}}
{{{600+240=840}}}
{{{840=840}}}
Thank you,
Jojo