if the ratio is 1:6, and its yellow to total, that means that you would need to subract 1 from 6 to get the number to blue counters needed to get the correct ratio
If they charge $20 per truck and washed 15, it would be $300. So you subtract $460 from $300. That gives you $160. Then, you divide $160 from $10. That gives you 16.
