age problems

[dentalstudent2021]

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do you guys use chads method or write system of equations and then solve ?

or any other methods ?

ex: Rachel is now 27 years older than her daughter, but in 8 years, Rachel will be 7 years younger than 3 times her daughter’s age. How old is Rachel now?
27, 36, 33, 34

 

[stewfoo412]

I go straight to the answer choices on these problems and mentally plug the answers in until one works. I wouldn't waste time writing anything down unless you can't do it in your head. Good luck.

 

[hye340]

there is a D variable,wat do we do with that?and why is it 7+3(d+8).why isn't it minus 7 cause it says younger?
thanks very much

 

[mrdeez]

there is a D variable,wat do we do with that?and why is it 7+3(d+8).why isn't it minus 7 cause it says younger?
thanks very much

I had minus 7 like you have, set that equal to 27 + D, solve for D, and then add 27. I got 34.

 

[stewfoo412]

The answer is 36!

 

[clutchfans]

I just wrote each scenario out as separate equations and used systems of equations.

R = 27+d
R+8 = 3d -7

d=21 and R=48

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It should be 3(d+8)-7 because Rachel's daughter also grows up

 

[DAT Destroyer]

do you guys use chads method or write system of equations and then solve ?

or any other methods ?

ex: Rachel is now 27 years older than her daughter, but in 8 years, Rachel will be 7 years younger than 3 times her daughter’s age. How old is Rachel now?

27, 36, 33, 34

R = 27 + D
R + 8 = 3(D + 8) - 7
And the answer is 36.

If you decide to back solve proceed as follow:
Let's say we pick 27 for R then her daughter is 0 years old. In 8 years Rachel will be 27+8=35 and her daughter will be 8 years old. 3*8-7= 17 which is not equal to 35.
If you pick 36 for Rachel, her daughter is 36-27= 9. In 8 years Rachel will be 44 and her daughter will be 17. 3*17-7=44

 

[hye340]

R = 27 + D
R + 8 = 3(D + 8) - 7
And the answer is 36.

If you decide to back solve proceed as follow:
Let's say we pick 27 for R then her daughter is 0 years old. In 8 years Rachel will be 27+8=35 and her daughter will be 8 years old. 3*8-7= 17 which is not equal to 35.
If you pick 36 for Rachel, her daughter is 36-27= 9. In 8 years Rachel will be 44 and her daughter will be 17. 3*17-7=44

so wait the 29 was the wrong answer?its 36.im confused thanks a lot

 

[DAT Destroyer]

so wait the 29 was the wrong answer?its 36.im confused thanks a lot

Yes 36 is the right answer.