Hello,
The following is from the OG quant book. I have tried solving it algebraically, but it never comes out correctly. Plugging in numbers works, but I want to know why Algebra isn't working.
Today Rose is twice as old as Sam and Sam is 3 years younger than Tina. If Rose, Sam, and Tina are all alive 4 years from today, which of the following must be true on that day.
I. Rose is twice as old as Sam
II. Sam is 3 years younger than Tina
III. Rose is older than Tina
(A) I only
(B) II only
(C) III only
(D) I and II
(E) II and III
OA is B
Here's my algebra:
R=2S
S=T-3
In 4 years:
R+4=2(S+4)
R+4=2S+8
R=2S+4
So (I) is correct by this algebra, but the correct answer says (I) doesn't work. What's wrong with my algebra here?
The following is from the OG quant book. I have tried solving it algebraically, but it never comes out correctly. Plugging in numbers works, but I want to know why Algebra isn't working.
Today Rose is twice as old as Sam and Sam is 3 years younger than Tina. If Rose, Sam, and Tina are all alive 4 years from today, which of the following must be true on that day.
I. Rose is twice as old as Sam
II. Sam is 3 years younger than Tina
III. Rose is older than Tina
(A) I only
(B) II only
(C) III only
(D) I and II
(E) II and III
OA is B
Here's my algebra:
R=2S
S=T-3
In 4 years:
R+4=2(S+4)
R+4=2S+8
R=2S+4
So (I) is correct by this algebra, but the correct answer says (I) doesn't work. What's wrong with my algebra here?
