<p>Hi,</p>
<p>I am future act test taker who has been scoring within the 33-36 range on ACT practice tests, and I always do extremely well within the science section. I was going through the practice test on the ACT website and although it is unlikely, I believe question five within the fifth passage of the science test has two correct answers. Hopefully, I will be proven wrong, but I am a bit concerned if the test makers could make an error like this. </p>
<p>To see the question and their right and wrong answers, follow this link.
[ACT</a> Sample Questions : Science Set 5](<a href=“ACT Test Preparation | Test Prep Resources | ACT”>ACT Test Preparation | Test Prep Resources | ACT)</p>
<p>The Question states:</p>
<p>Based on the information in Table 1, to best identify a metal ion using paper chromatography, one should know the:</p>
<p>A.spot color for the ion only.
B.distance the solvent traveled only.
C.Rf value and spot color for the ion only.
D.distance the solvent traveled and spot color of the ion only.</p>
<p>It says choice C is correct, as the spot color for ion only will not work since their are two samples with a brown-color; all of this I agree with. The problem comes with the RF value vs the distance the solvent traveled. These numbers are the same, only the rf value has multiplied the value by .1 (ie, distance solvent traveled = .8 then rf value -= .08). Because these values maintain the same ratio, I cannot see how one can correctly choose between the choices of rf value and spot color for the ion only and distance the solvent traveled and spot color only. I must be (or am hoping that) I am missing something very obvious here, if I am someone please point it out to me. Edit: Could it be that the question states “best (way to) identify” and for some reason they decided that the rf was a better way to identify than the solvent even though their mathematical ratios are the same?</p>
<p>Thanks</p>