GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If x, y, and z are positive integers, x : y = 1 : 3, and z : y = 2 : 5
[#permalink]
04 Feb 2021, 08:36
04 Feb 2021, 08:36
1
Expert Reply
1
Bookmarks
00:00
Question Stats:
80% (01:20) correct
20% (02:12) wrong based on 25 sessions
Hide Show timer Statistics
If x, y, and z are positive integers, x : y = 1 : 3, and z : y = 2 : 5, then x + z COULD equal
A) 46
B) 50
C) 54
D) 62
E) 66
Kudos for the right answer and explanation
A) 46
B) 50
C) 54
D) 62
E) 66
Kudos for the right answer and explanation
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If x, y, and z are positive integers, x : y = 1 : 3, and z : y = 2 : 5
[#permalink]
04 Feb 2021, 10:32
04 Feb 2021, 10:32
2
1
Bookmarks
Carcass wrote:
If x, y, and z are positive integers, x : y = 1 : 3, and z : y = 2 : 5, then x + z COULD equal
A) 46
B) 50
C) 54
D) 62
E) 66
Kudos for the right answer and explanation
A) 46
B) 50
C) 54
D) 62
E) 66
Kudos for the right answer and explanation
Given: x : y = 1 : 3
y : z = 5 : 2
To COMBINE these ratios, their shared term (the y-value) must be the same in each ratio.
So, take x : y = 1 : 3 and multiply both parts by 5 to get an EQUIVALENT RATIO: x : y = 5 : 15
Likewise, take y : z = 5 : 2 and multiply both parts by 3 to get: y : z = 15 : 6
We can now COMBINE the ratios to get: x : y : z = 5 : 15 : 6
This means the ratio x : z = 5 : 6
Since x and z are positive integers, x + z must be a MULTIPLE of 5 + 6
In other words, x + z must be a MULTIPLE of 11
Answer: E
If x, y, and z are positive integers, x : y = 1 : 3, and z : y = 2 : 5
[#permalink]
09 Feb 2022, 00:56
09 Feb 2022, 00:56
x/y = 1/3
z/y = 2/5
Flip z/y:
y/z = 5/2
Multiply the ratios (notice the y cancels out since y is in the numerator and denominator):
(x/y)(y/z) = x/z
(1/3)(5/2) = 5/6
x + z = 5 + 6 = 11
66 is a multiple of 11
Answer E
z/y = 2/5
Flip z/y:
y/z = 5/2
Multiply the ratios (notice the y cancels out since y is in the numerator and denominator):
(x/y)(y/z) = x/z
(1/3)(5/2) = 5/6
x + z = 5 + 6 = 11
66 is a multiple of 11
Answer E
