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A satellite is composed of 30 modular units, each of...

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A satellite is composed of 30 modular units, each of...

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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. 1/24

The OA is D.

I'm confused with this PS question. Experts, any suggestion about the solution? Thanks in advance.

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LUANDATO 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. 1/24
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

Answer: D

Cheers,
Brent

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LUANDATO 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. 1/24

The OA is D.

I'm confused with this PS question. Experts, any suggestion about the solution? Thanks in advance.
Or pick an easy number.

Total # of upgraded sensors on 30 units. = 5.
# of non-upgraded sensors on one unit = (1/5)*5 = 1
# of total non-upgraded sensors on 30 units = 1*30 = 30
Total # of sensors = 5 + 30 = 35.
Upgraded/Total = 5/35 = 1/7- The answer is D

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Posted:
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122 members
Upvotes:
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Post
LUANDATO 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. 1/24

The OA is D.

I'm confused with this PS question. Experts, any suggestion about the solution? Thanks in advance.
Call the total # of upgraded sensors 'u.'
The # of non-upgraded sensors on one unit = (1/5)u
# of non-upgraded inits on 30 units = (1/5)u * 30 = 6u

If there are 'u' upgraded sensors and 6u non-upgraded sensors, then there would be 7u sensors in total. Upgraded/Total = u/7u =1/7. The answer is D

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