Official Explanation:Let the number of sonograms be n
Let the number of x-rays be m
Let the average time taken by the nurse to assist with a sonogram be s
Let the average time taken by the nurse to assist with an x-ray be x
Since the nurse assisted in twice as many sonograms as x—rays, n = 2m (Equation I)
Total amount of time spent by the nurse to assist with sonograms = ns
Total amount of time spent by the nurse to assist with x-rays = mx
We need to find whether ns > mx
From Equation 1, this can also be expressed as: 2ms > mx
Cancelling “m” from both sides, we get: 2s > x
We need to find whether 2s > xStatement (1)x = s + 10 (Equation II)
Possibility 1: If s = 100, then x = 112 and 2s is greater than x.
Possibility 2: If s = 1, then x = 11 and 2s is NOT greater than x.
It is NOT possible to determine with certainty whether the total time spent by the nurse in assisting with sonograms was greater than the amount of time she spent assisting with x-rays.
Hence, Statement (1) is insufficient.Statement (2)(ns+mx)/(n+m) > 11
(ns + mx) > 11(n + m)
From Equation I, we get: (2ms + mx) > 11(2m + m)
(2ms + mx) > 11(3m)
Cancelling “m” from both sides, we get: (2s + x) > 33 (Equation III)
Possibility 1: If s = 100 and x = 1, then 2s is greater than x.
Possibility 2: If s = 1 and x = 100, then 2s is NOT greater than x.
It is NOT possible to determine with certainty whether the total time spent by the nurse in assisting with sonograms was greater than the amount of time she spent assisting with x—rays.
Hence, Statement (2) is insufficient.As Statement (1) alone as well as Statement (2) alone is insufficient to answer the question, we need to now combine the two statements.
Statement (1) and Statement (2) combinedFrom Equation III; we get (2s + x) > 33
Substituting the value of “x” from Equation II in Equation III, we get;
2s + s + 10 > 33
3s + 10 > 33
3s > 23
s > 6.67
Possibility 1: If s = 7, then x = (s + 10) = 17. In this case, 2s is NOT greater than x.
Possibility 2: If s = 100, then x = (s + 10) = 110. In this case, 2s is greater than x.
It is NOT possible to determine with certainty whether the total time spent by the nurse in assisting with sonograms was greater than the amount of time she spent assisting with x-rays.
Hence, Statement (1) and Statement (2) combined are insufficient.E is the correct answer choice.