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The present ages of three persons are in the proportion of 5:8:7. Eigh
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08 Apr 2021, 01:50
08 Apr 2021, 01:50
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The present ages of three persons are in the proportion of 5:8:7. Eight years ago, the sum of their ages was 76. Find the present age of the youngest person.
(A) 15
(B) 20
(C) 25
(D) 30
(E) 32
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
(A) 15
(B) 20
(C) 25
(D) 30
(E) 32
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
Re: The present ages of three persons are in the proportion of 5:8:7. Eigh
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08 Apr 2021, 04:30
08 Apr 2021, 04:30
Let the ages are 5x,8x,7x
Eight years ago they were 5x-8,8x-8,7x-8
and Total is 76
-> 5x-8+8x-8+7x-8=76
Solving for x-> x=5
Hence the present age of the youngest person is 5x=25
Correct answer is C
Eight years ago they were 5x-8,8x-8,7x-8
and Total is 76
-> 5x-8+8x-8+7x-8=76
Solving for x-> x=5
Hence the present age of the youngest person is 5x=25
Correct answer is C
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Re: The present ages of three persons are in the proportion of 5:8:7. Eigh
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08 Apr 2021, 05:26
08 Apr 2021, 05:26
1
Carcass wrote:
The present ages of three persons are in the proportion of 5:8:7. Eight years ago, the sum of their ages was 76. Find the present age of the youngest person.
(A) 15
(B) 20
(C) 25
(D) 30
(E) 32
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
(A) 15
(B) 20
(C) 25
(D) 30
(E) 32
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
The present ages of three persons are in the proportion of 5 : 8 : 7
So, the three ages COULD be 5, 8 and 7
Or, the three ages COULD be 10, 16 and 14
Or, the three ages COULD be 15, 24 and 21
Or, the three ages COULD be 20, 32 and 28
.
.
.
etc.
Notice that the 3 present ages will always be multiples of 5, 8 and 7 respectively.
So, we could write.....
Let 5x = PRESENT age of youngest person
Let 8x = PRESENT age of oldest person
Let 7x = PRESENT age of middle person
Eight years ago, the sum of their ages was 76
Eight years ago, the ages were are follows:
5x - 8 = age of youngest person
8x - 8 = age of oldest person
7x - 8 = age of middle person
So, we can write: (5x - 8) + (8x - 8) + (7x - 8) = 76
Simplify: 20x - 24 = 76
So, 20x = 100
Solve: x = 5
5x = PRESENT age of youngest person
So, the present age of the youngest person = 5(5) = 25
Answer: C
