Question 1167271
x, for how many pictures

<pre>
OPTIONS                    COSTS
$25 and 0.4 per pic        0.4x+25
$30 and 0.15 per pic       0.15x+30
</pre>


The important boundary for x is for when {{{0.4x+25=0.15x+30}}}.
Maybe you can figure out the rest.