Question 1172284
.
<pre>

The ratio of the areas is  1200/350 = 24/7.


So, the ratio of the paint volumes is  24/7, too.


The number of units of magenta is 3 per each quart, or 3*4 = 12 units per gallon.


Hence, the number of units of magenta is  24/7 times 12, or  {{{(24*12)/7}}} = {{{288/7}}} = 41 {{{1/7}}} for the mural of 1200 sq ft.


Round it as you want.
</pre>

Solved.


That's all.