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Today Jack is twice as old as Mary was 9 years ago. How old is Mary to
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22 May 2022, 22:24
22 May 2022, 22:24
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Today Jack is twice as old as Mary was 9 years ago. How old is Mary today in terms of Jack's current age, Y?
(A)Y+ 9
(B)Y+ 18
(C) (Y + 9)/2
(D) (Y + 18)/2
(E) (Y/2) - 9
(A)Y+ 9
(B)Y+ 18
(C) (Y + 9)/2
(D) (Y + 18)/2
(E) (Y/2) - 9
Part of the project: Skill Builder Project for a Q170
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GRE Math Essentials
GRE Geometry Formulas for a Q170
GRE - Math Book
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GRE Math Essentials
GRE Geometry Formulas for a Q170
GRE - Math Book
Re: Today Jack is twice as old as Mary was 9 years ago. How old is Mary to
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22 May 2022, 22:52
22 May 2022, 22:52
I solved it algebraically. Any 10s-30s approach would be much appreciated. Please let me know.
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Today Jack is twice as old as Mary was 9 years ago. How old is Mary to
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23 May 2022, 06:31
23 May 2022, 06:31
Carcass wrote:
Today Jack is twice as old as Mary was 9 years ago. How old is Mary today in terms of Jack's current age, Y?
(A)Y+ 9
(B)Y+ 18
(C) (Y + 9)/2
(D) (Y + 18)/2
(E) (Y/2) - 9
(A)Y+ 9
(B)Y+ 18
(C) (Y + 9)/2
(D) (Y + 18)/2
(E) (Y/2) - 9
Let Y = Jack's PRESENT age
Let M = Mary's PRESENT age
Today Jack is twice as old as Mary was 9 years ago.
We can write: Y = 2(M - 9)
How old is Mary today in terms of Jack's current age, Y?
So, we must solve our newly-created equation for M
Take: Y = 2(M - 9)
Divide both sides by 2 to get: Y/2 = M - 9
Add 9 to both sides: Y/2 + 9 = M
Check the answer choices . . . not there.
Looks like we need to combine Y/2 + 9 into one fraction.
Rewrite 9 as follows: Y/2 + 18/2 = M
Combine fractions: (Y + 18)/2 = M
Answer: D
