Jay can buy a stereo either online or at the local store. If he buys online he gets a 15% discount, but has to pay a $12 shipping fee. At the local store, The stereo is not on sale, but there is no shipping fee. For what regular price is it cheaper for J to buy the stereo online
15% discount means u r paying 85% for it
x = original price
0.85x + 12 < x
12 < x - 0.85x
12 < 0.15x
12/0.15 < x
80 < x.....so for it to be cheaper online, it would have to cost more then 80....so 81 or higher
Let
x------> the regular price of the stereo in dollars
we know that
If Jay buy a stereo online
He has to pay
\(x(1-0.15)+\$12=0.85x+\$12\)
If Jay buy a stereo at the local store
He has to pay
\(x\)
Is cheaper for Jay to buy the stereo online when
\(0.85x+\$12 < x\\0 .85x-x < -12\\- 0.15x < -12\\ 0.15x > 12\\ x > 12/0.15\\ x > \$80\)
therefore
the answer is
The regular price must be greater than \(\$80\) for Jay to buy the stereo on line