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In ten years, David will be four times as old as Aaron. Twenty years a
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17 May 2022, 01:50
17 May 2022, 01:50
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In ten years, David will be four times as old as Aaron. Twenty years ago, David was twice as old as Ellen. If David is seven years older than Ellen, how old is Aaron?
A. 1–5
B. 6–10
C. 11–15
D. 16–20
E. 21–25
A. 1–5
B. 6–10
C. 11–15
D. 16–20
E. 21–25
Part of the project: GRE QCQ & PS 3 Questions Every One DAILY Challenge - (2022)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
Re: In ten years, David will be four times as old as Aaron. Twenty years a
[#permalink]
17 May 2022, 04:26
17 May 2022, 04:26
1
Consider D1 to be the age of David 20 yrs ago and E1 to be the age of Ellen 20 yrs ago. Then as per the stem, D1=2E1
The present Age of David(D) is 7 yrs more than Ellen(E). D=E+7
Also D1+20=D, E1+20=E as 20 yrs have progressed since then. Substituting these two in the equation D1=2E1 we get
D-20=2(E-20)
Also as D=E+7, we can further substitute in the same equation.
D-20=2(D-7-20)
D-20=2D-54
D=34(Current age of David)
In 10 yrs, David will be 4 times Aaron's age which implies D+10=4(A)
4A=44
A=11(This is Aaron's age 10 yrs from now)
Therefore the current Age of Aaron is 11-10=1. Option A
I'm sure there is a simpler way to solve this. Please do post below if you find out.
The present Age of David(D) is 7 yrs more than Ellen(E). D=E+7
Also D1+20=D, E1+20=E as 20 yrs have progressed since then. Substituting these two in the equation D1=2E1 we get
D-20=2(E-20)
Also as D=E+7, we can further substitute in the same equation.
D-20=2(D-7-20)
D-20=2D-54
D=34(Current age of David)
In 10 yrs, David will be 4 times Aaron's age which implies D+10=4(A)
4A=44
A=11(This is Aaron's age 10 yrs from now)
Therefore the current Age of Aaron is 11-10=1. Option A
I'm sure there is a simpler way to solve this. Please do post below if you find out.
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Re: In ten years, David will be four times as old as Aaron. Twenty years a
[#permalink]
17 May 2022, 05:10
17 May 2022, 05:10
Carcass wrote:
In ten years, David will be four times as old as Aaron. Twenty years ago, David was twice as old as Ellen. If David is seven years older than Ellen, how old is Aaron?
A. 1–5
B. 6–10
C. 11–15
D. 16–20
E. 21–25
A. 1–5
B. 6–10
C. 11–15
D. 16–20
E. 21–25
Part of the project: GRE QCQ & PS 3 Questions Every One DAILY Challenge - (2022)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
David is seven years older than Ellen
So, if we let E = Ellen's PRESENT age...
Then E + 7 = David's PRESENT age
Twenty years ago, David was twice as old as Ellen
20 YEARS AGO, Ellen's age = E - 20
20 YEARS AGO, David's age = (E + 7) - 20 = E - 13
So, we can write: E - 13 = 2(E - 20)
Solve to get: E = 27, which means Ellen's PRESENT age is 27, which means David's PRESENT age is 34 (7 years older than Ellen)
In ten years, David will be four times as old as Aaron
Since David's PRESENT age is 34, we know that, IN 10 YEARS, David's age will be 44, which means Aaron will be 11 years old IN 10 YEARS.
How old is Aaron?
If Aaron will be 11 years old IN 10 YEARS, we know that Aaron's PRESENT age is 1.
Answer: A
