How Many DoctorsMath brain teasers require computations to solve.
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?
AnswerThe total attendance was 75.
x = total attendance
x-40 = total cardiologists
x-50 = total pediatricians
x-60 = total surgeons
x = x-40 + x-50 + x-60
x = 3x - 150
-2x = -150
x = 75
75 total attendees
See another brain teaser just like this one...
Or, just get a random brain teaser
If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.
Back to Top