Brain Teasers
How Many Doctors
A group of doctors attended a conference. All but 40 were cardiologists. All but 50 were pediatricians. All but 60 were surgeons. These were the only types of doctors in attendance. How many in all attended the conference?
Answer
The total attendance was 75.x = total attendance
x-40 = total cardiologists
x-50 = total pediatricians
x-60 = total surgeons
Final equation:
x = x-40 + x-50 + x-60
x = 3x - 150
-2x = -150
x = 75
35 cardiologists
25 pediatricians
15 surgeons
----
75 total attendees
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Comments
Fun! At first I thought it could be 61, with overlap between doctor types. Then I decided they had to be different and found the individual numbers of doctors, then added them up.
The question needs to be fixed to indicate that exactly three types of doctors were in attendance. As-is there are 16 answers. Zero surgeons, 10 pediatricians, 20 cardiologists and 30 others for total of 60. 1, 11, 21 and 28 for 61. 2, 12, 22 and 26 for 62. An so forth until you get 15, 25, 35 and no others for total of 75.
and surgeons are one of the three types.
I added a correction that noted they are the only 3 types of doctors present. Better?
Epic win
I realized that as stated, there were multiple correct answers - or at least, multiple non-incorrect answers!
Unless, of course, the specialties are to be considered exclusive. As in, a cardiologist cannot be a pediatrician for this teaser, etc.
Nice thought but IMO needs more qualification.
Thanks!
Jim
Unless, of course, the specialties are to be considered exclusive. As in, a cardiologist cannot be a pediatrician for this teaser, etc.
Nice thought but IMO needs more qualification.
Thanks!
Jim
Fun quiz... very nice
used a chart bc didnt take algebra yet
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