To find: Is y − x < 60 ?
(1) When x and y are rounded to the nearest unit, the results are 15 and 75, respectively.
=> Value of X when rounded to nearest unit digit = 15
So value of X can range from 14.51 ≤ X ≤15.49
=> Value of Y when rounded to nearest unit digit = 75
So value of Y can range from 74.51 ≤ Y ≤75.49
Putting extreme values in Y-X
Case 1: Y = 75.49 & X = 14.51
75.49-14.51 > 60
60.98 > 60 (correct)
Case 2: Y = 74.51 & X = 15.49
74.51-15.49 > 60
59.02 > 60 (Incorrect)
(Insufficient)
(2) When x and y are rounded to the nearest ten, the results are 20 and 70, respectively.
=> Value of X when rounded to nearest ten digit = 20
So value of X can range from 15.01 ≤ X ≤ 24.99
=> Value of Y when rounded to nearest ten digit = 70
So value of Y can range from 65.01 ≤ Y ≤74.99
Putting extreme values in Y-X
Case 1: Y = 74.99 & X = 15.01
74.99-15.01 > 60
59.98 > 60 (incorrect)
Case 2: Y = 65.01 & X = 24.99
65.01-24.99 > 60
40.02 > 60 (Incorrect)
(Sufficient)
Answer is B
Posted from my mobile device