A satellite is composed of 24 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 1/4 the total number of upgraded sensors on the entire satellite, what fraction of the sensors on the satellite have been upgraded? Choose the correct choice from the following options: A) 5/6 B) 1/5 C) 1/6 D) 1/7 E) 1/24
Let x be the number of upgraded sensors on the satellite.   The number of non-upgraded sensors per unit is x/4.   The number of non-upgraded sensors on the whole satellite is 24(x/4) = 6x.   The fraction of sensors which have been upgraded is x / (x+6x) = x/7x = 1/7   The answer is 1/7.
<result>D</result>
A satellite is composed of 24 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 1/4 the total number of upgraded sensors on the entire satellite, what fraction of the sensors on the satellite have been upgraded?