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One Friday night, two large groups of people called centerville taxi service.
The first group requested 3 sedans and 2 minivans, which can seat a total of 21 people.
The second group asked for 3 sedans and 3 minivans, which can seat a total of 27 people.
How many passengers can each type of taxi seat?
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This problem is for MENTAL solution, and the solution is in two lines:
1. The difference of 27-21 = 6 is exactly the number of peoples that can seat in minivan.
2. From the part related to the 2-nd group, you see that 1 sedan plus one minivan can carry 9 passengers.
Then from n.1 you get that each sedan carries 9-6 = 3 passengers.
Solved.
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To see other similar solved problems, look into the lesson
- Solving mentally word problems on two equations in two unknowns
in this site.
The problems like this are good at the interview for a Math position, when the interviewer wants to check if the interviewed person
has a creative mind.
If after reading the condition the interviewed person starts writing systems of equation, the interviewer writes "-" in his checklist.
If the interviewed person solves the problem mentally, in a way as I showed it in my solution, the interviewer writes "+" in his checklist.
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Ignore writing by @josgarithmetic, because it is nonsense.