Explanation for Question 51 From the Reading Section on the 2019 March Sat
Question number 51 says based on data in the figure, 2 which choice is a reasonable conclusion about lunar glass bead green, 3 number five. So this is the subject. 4 All of our data refers to this glass beet green, 5 number five. So we want to see which of these statements is best backed 6 up by the graph itself. So choice a says beyond a hundred micrometres 7 from its core. Water is not detectable. 8 So this is clearly untrue given that we have some 9 level of detection here around 12 for 120. 10 Um, and that's obviously greater than 100. 11 So clearly, uh, there is some level of detectability past 100. 12 So choice a is out choice. B says at no point in time, 13 did its water concentration exceed 30 parts per million. 14 Um, this graph reflects one moment in time. 15 Time is not a variable that is expressed on either axis. 16 We're looking at water, concentration and distance from the core. 17 So nothing about over time. 18 So we can't make any statements about that. Choice. 19 B is out, uh, answer choice. 20 C says it's water concentration at 120 is approximately half 21 that at its core. So we see that at 120, 22 the concentration is maybe a little bit less than 15 around 15 23 in that ballpark. Um, meanwhile at the core it's about 30. 24 So 15 is half of 30. 25 So that statement looks correct. 26 Uh, answer choice D its water. Concentration is 50% less than it. 27 Once was again, that's making a comparison over time, 28 just like we did in B. Um, 29 and because time isn't reflected on either access and this graph really doesn't make 30 any statements about time. We have to roll out D as well. 31 So answer choice C is our best choice water concentration, 32 120 is approximately half that at its core. 33 And we were able to validate that on the graph, 34 looking at these values of 15 and 30. 35 So answer choice C for a number 15.