Question 878215
The question and description in simpler wording is:
How much 0.3% sulfur content fuel should be mixed with 120000 gallons of 0.9% sulfur fuel to make a blend of fuel which is 0.8% sulfur?


This type of mixture problem is discussed and solved in this lesson:
<a href="http://www.algebra.com/tutors/Two-Part-Mixture-with-one-material-quantity-unknown.lesson?content_action=show_dev">Mixture: one material quantity unknown </a>