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# A satellite is composed of 30 modular units, each of which

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Joined: 10 Apr 2015
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A satellite is composed of 30 modular units, each of which [#permalink]  23 Sep 2016, 14:16
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Question Stats:

37% (02:13) correct 62% (01:57) wrong based on 35 sessions
A satellite is composed of 30 modular units, each of which is equipped with a set of sensors, some of which have been upgraded. Each unit contains the same number of non-upgraded sensors. If the number of non-upgraded sensors on one unit is 1/5 the total number of upgraded sensors on the entire satellite, what fraction of the sensors on the satellite have been upgraded?

A)5/6
B)1/5
C)1/6
D)1/7
E)1/2
[Reveal] Spoiler: OA

_________________

Brent Hanneson – Creator of greenlighttestprep.com

GRE Instructor
Joined: 10 Apr 2015
Posts: 2290
Followers: 71

Kudos [?]: 2165 [3] , given: 26

Re: A satellite is composed of 30 modular units, each of which [#permalink]  23 Sep 2016, 14:17
3
KUDOS
Expert's post
GreenlightTestPrep wrote:
A satellite is composed of 30 modular units, each of which is equipped with a set of sensors, some of which have been upgraded. Each unit contains the same number of non-upgraded sensors. If the number of non-upgraded sensors on one unit is 1/5 the total number of upgraded sensors on the entire satellite, what fraction of the sensors on the satellite have been upgraded?

A)5/6
B)1/5
C)1/6
D)1/7
E)1/2

Since we're asked to find a certain FRACTION, we can plug in some nice values that meet the given conditions.

Let's say that there's a TOTAL of 5 upgraded sensors on the entire satellite

the number of non-upgraded sensors on one modular unit is 1/5 the TOTAL number of upgraded sensors on the entire satellite
So, the number of non-upgraded sensors on EACH modular unit = (1/5)(5) = 1.

Since there are 30 modular units altogether, the TOTAL number of non-upgraded sensors = (30)(1) = 30.

So, the TOTAL number of sensors = (number of non-upgrades) + (number of upgraded)
= 30 + 5
= 35

What fraction of the sensors on the satellite have been upgraded?
= 5/35
= 1/7

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com

Intern
Joined: 14 Sep 2017
Posts: 1
Followers: 0

Kudos [?]: 1 [1] , given: 1

Re: A satellite is composed of 30 modular units, each of which [#permalink]  03 Jul 2018, 06:27
1
KUDOS
Let, non-upgradable sensor per module (or 1 module) = x
Total no. of sensor = T
Total no. of upgraded sensors = y = T - 30x
Logic line: x = (1/5)*y So, y = 5x
or, x = (1/5)*(T - 30x)
solving, T = 35x
so, y/T = 5x/35x = 1/7
GRE Instructor
Joined: 10 Apr 2015
Posts: 2290
Followers: 71

Kudos [?]: 2165 [2] , given: 26

Re: A satellite is composed of 30 modular units, each of which [#permalink]  11 Jul 2019, 06:42
2
KUDOS
Expert's post
GreenlightTestPrep wrote:
A satellite is composed of 30 modular units, each of which is equipped with a set of sensors, some of which have been upgraded. Each unit contains the same number of non-upgraded sensors. If the number of non-upgraded sensors on one unit is 1/5 the total number of upgraded sensors on the entire satellite, what fraction of the sensors on the satellite have been upgraded?

A)5/6
B)1/5
C)1/6
D)1/7
E)1/2

Let's say that there's a TOTAL of x upgraded sensors on the entire satellite

the number of non-upgraded sensors on one modular unit is 1/5 the TOTAL number of upgraded sensors on the entire satellite
So, the number of non-upgraded sensors on EACH modular unit = (1/5)(x) = x/5.

Since there are 30 modular units altogether, the TOTAL number of non-upgraded sensors = (30)(x/5) = 30x/5 = 6x.

So, the TOTAL number of sensors = (number of non-upgrades) + (number of upgraded)
= 6x + x
= 7x

What fraction of the sensors on the satellite have been upgraded?
= x/7x
= 1/7

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com

Intern
Joined: 23 Jul 2019
Posts: 3
Followers: 0

Kudos [?]: 1 [0], given: 11

Re: A satellite is composed of 30 modular units, each of which [#permalink]  06 Aug 2019, 23:05
Let no. of non-upgraded sensors per module be x
Total non-upgraded sensors = 30x (since each module has same no. of non-upgraded sensors)

Let total upgraded sensors be T
From given condition: x=1/5*T
or, T= 5x

Now,

Total no. of sensors = 5x+30x = 35x

so fraction of upgraded = 5x/35x = 1/7

Intern
Joined: 01 Aug 2019
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: A satellite is composed of 30 modular units, each of which [#permalink]  07 Aug 2019, 00:24
Wow, this is the topic! How much I know, but this is the first time I've ever met! Wow!
Re: A satellite is composed of 30 modular units, each of which   [#permalink] 07 Aug 2019, 00:24
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