AboutAbe Mantell Expertise Hello, I am a college professor of mathematics and regularly teach all levels from elementary mathematics through differential equations, and would be happy to assist anyone with such questions!
Experience Over 15 years teaching at the college level.
SIr Teruel wrote at 2009-09-02 17:51:56
Theres something wrong on how you understood the question. It states there that 78% neither had license nor were charged for parking ticket. So it means that there is still 22% remaining. 15% of which dont have driving license(take note that there is a possibility that those people might have been charged as well for parking ticket). It also stated in the problem that 10% were charged for parking ticket(again, there is a possibility that some of those people dont have their driving license). In short: 78% neither; (the remaining 22% is distributed in 3 categories:
1. dont have driving license ONLY
2. charged for parking lot ONLY
3. dont have license and were charged--> this is the one being asked in the problem)
that would be:
100%-78%=22%
22%=(dont have license) + (were charged) - (both dont have license and were charged)
Numerically:
22=15+10-X
X=15+10-22
X=3(both were charged and no license)
Therefore:
dont have license ONLY: 12%(15-3)
were charged ONLY: 7% (10-3)
both= 3%
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TOTAL: 22%
