word problems

[mobius]

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janes age is 2.5 times davids age. in 15 years janes age will be twice davids age. how old was jane 8 years ago?



kims is 1/3 the age of her older sistersue. in 13 years, sue will be one year younger than twice im's age. how old is sue?


anyone want to take a stab???

 

[BAJackson16]

K = 1/3 S or S=3K
S+13=2(K+13)-1

 

[mobius]

how bout a number? for each one.

 

[rocknightmare]

jane is 67 years old 8 years ago.

J=2.5D
J+15=2D
2.5D+15=2D
D=30

J=2(30)+15 - 8=67

as another poster has said..

 

[Rezdawg]

Worst case scenario, do a trial and error with the answer choices given.

 

[weiy01]

Since J=2.5D and D=30 from the calculation above. Jane is J=(2.5(30))-8. The correct answer, I believe, is 67. 🙂 I think it was just a simple error, but good job!

This is my first post 🙂

 

[rocknightmare]

lol you are right..

 

[mobius]

wouldnt the correct answer be 62? since jane is equla o 2.5 david and it asks for janes age 8 years ago.... so 2.5(30)-8 = 62