Gmat_mission wrote: ↑Sat Oct 31, 2020 6:44 am
If Randy has twice as many coins as Alice, and if Maria has 7 times as many coins as Alice, what is the combined number of coins that all three of them have?
(1) Alice has 4 fewer coins than Randy.
(2) Maria has 20 more coins than Randy.
Answer:
D
Source: GMAT Prep
Given: Randy has twice as many coins as Alice, and if Maria has 7 times as many coins as Alice
Target question: What is the combined number of coins that all three of them have?
This is a good candidate for
rephrasing the target question.
Let
A = the number of coins Alice has
So
2A = the number of coins Randy has
And
7A = the number of coins Maria has
So, the COMBINED number of coins they have = A + 2A + 7A =
10A
REPHRASED target question: What is the value of 10A?
Aside: the video below has tips on rephrasing the target question
Statement 1: Alice has 4 fewer coins than Randy.
In other words: (the number of coins Alice has) = (the number of coins Randy has) - 4
Substitute to get:
A =
2A - 4
Solve to get: A = 4, which means
10A = 40
Since we can answer the
REPHRASED target question with certainty, statement 1 is SUFFICIENT
Statement 2: Maria has 20 more coins than Randy.
In other words: (the number of coins Maria has) = (the number of coins Randy has) + 20
Substitute to get:
7A =
2A + 20
Solve to get: A = 4, which means
10A = 40
Since we can answer the
REPHRASED target question with certainty, statement 2 is SUFFICIENT
Answer: D
Cheers,
Brent
