math age wp

[Electrons]

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The average of a married couple and a daughter three years ago was 27 years and that of mom and daughter five years ago was 20 years. What is the father's present age?

Answer is :41


According to my math setup it should be 40. Am I correct unless my setup is wrong?


(F + W + S)/3 - 3 =27


(W + S)/2 - 5=20


calc:
F + W + S = 90
W + S = 50



sub bottom eq to top and get F = 40.

 

[baedero1]

i think its 40
i also got 40

 

[Jul18]

The average of a married couple and a daughter three years ago was 27 years and that of mom and daughter five years ago was 20 years. What is the father's present age?

Answer is :41


(W + F + D/3) - 3 = 27

(W + D)/2 -5 = 20

W+ D = 25(2) = 50

50 + F/3 = 30

50 + F = 90

F = 40

 

[klutzy1987]

1) (m-3+f-3+d-3)/3=27
2) (m-5+d-5)/2=20

1)therefore that formula rearranged=(m+f+d-9)/3=27 rearranging again gives m+f+d=90
2)Rearranging this formula gives (m+d-10)/2 =20 rearranging again gives m+d=50. Plugging this back into the formula gives 50+f=90. Therefore f=40.

 

[DentalDeac]

I also got 40