Weird Doctors' Stalker

Algebra Level 3

In an organization, there are engineers, accountants and doctors. The sum of the ages is 2,160; the average age is 36. The average age of the engineers and accountants is 39; of the accountants and doctors, 32 & 8/11; the engineers and doctors, 36 & 2/3. If each engineer were 1 year older, each accountant 6 years older, and each doctor 7 years older, their average age would be 41. Determine the number of doctors.

14 20 cannot be determined 38

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1 solution

It's easy but had a very long solution!

  1. Let nE=number of engineers nA=number of accountants nD=number of doctors E=sum of the ages of all engineers A=sum of the ages of all accountants D=sum of the ages of all doctors
  2. E+A+D=2,160
  3. (E+A+D)/(nE+nA+nD)=36
  4. (E+A)/(nE+nA)=39
  5. (A+D)/(nA+nD)=360/11
  6. (E+D)/(nE+nD)=110/3
  7. [E+1(nE)]+[A+6(nA)]+[D+7(nD)]/(nE+nA+nD)=41
  8. Combine #2 and #3---> (2,160)/(nE+nA+nD)=36 ----> therefore, nE+nA+nD=60
  9. Combine #2 and #7--->[(E+nE)+(A+6nA)+(D+7nD)]/(nE+nA+nD)=41 --->(nE+6nA+7nD+2,160)/(nE+nA+nD)=41 ---> therefore, 40nE+35nA+34nD=2,160

10.Combine #2 and #4--> 39(nE+nA)+D=2,160

11.Combine #2 and #5--> (360/11)(nA+nD)+E=2,160 12.Combine #2 and #6--> (110/3)(nE+nD)+A=2,160

13.Add #10,#11 and #12 to have: [(227nE)/3]+[(789nA)/11]+[(2,290nD)/33]=4320

14.Solving numbers(#) 8, 9, and 13 we obtain nE=16, nA=24, and nD=20. So the answer is 20!

The sum of the ages is 2016 in your que nd 2160 in your solution......!!!!!

Milind Joshi - 7 years ago

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Gosh!!! Sorry!!! I'd just mistaken, things I'd typed!!!

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Its okey..!!

Milind Joshi - 7 years ago

All the work I did to solve this and all for naught due to your typo! Wheesh! Cream puffs at 20 paces is the sentence for you.

Guiseppi Butel - 7 years ago

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Typo? You should just keep on your patience.

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For how long?

Guiseppi Butel - 7 years ago

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@Rhiana Vanessa Bag-id Amoin I challenge you to solve this problem with the original parameter of 2016 as the sum of the ages.

PS. Keep your patience until you're done.

Guiseppi Butel - 7 years ago

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@Guiseppi Butel Ok! If I have time

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@Rhiana Vanessa Bag-id Amoin Reserve lots of it! Good luck!

Guiseppi Butel - 7 years ago

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@Guiseppi Butel I have no time.

Why does this new format not provide a report option?

Guiseppi Butel - 7 years ago

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