Chloe has＄$$7$$. She is going to buy $$6$$ pens, and each costs $90$ cents. She also buys a certain number of pencils, and each costs $$50$$ cents. How many pencils at most can she buy? (Adapted from 2007 Math Kangaroo Problem, Level 3-4, Question \#4) 
Overseas Competition->Knowledge Point->Word Problem Modules->Unitary Method Problems->Finding the Total Value using Unitary Method
$7$ dollars =~ $700$ cents  $(700-6\times90)\div50=3R10$ 