<p>OK, these are two problems from Gruber's and their explanations are hopeless sometimes: </p>
<ol>
<li><p>A merchant marks down a certain lamp up 30% above original cost. Then, he gives a customer a 15% discount. If the final selling price of the lamp is $86.19, what was the original cost?
A. 66.30
B. 73.26
C. 78
D. 99.12
E. 101.40</p></li>
<li><p>If 10 men can survive for 24 days on 15 cans of rations, how many cans will be needed for 8 men to survive 36 days?
A. 15
B. 16
C. 17
D. 18
E. 19</p></li>
</ol>
<p>10 men used 15/24 = .625 rations per day. So 1 man used .0625 rations per day. 8 men will use .5 rations per day. 8 men will use 18 rations for 36 days since .5 * 36 = 18</p>
<p>1.3 comes from “A merchant marks down a certain lamp up 30% above original cost.” You wrote “marks down…above original cost” and An0maly ignored “marks down” and went with “30% above original cost”–1x being original cost and .3x being the added part to make 1.3x being the new price above the original cost.</p>
<p>Poor wording is standard fare for all non-original ETS questions. This and the lack of quality control and relevance all contribute to the problems in using synthetic tests. </p>
<p>Fwiw, to understand the spirit of the question, simply think that the original sales price should have included a standard profit of 60% to 100%. The merchant by only adding 30% is in fact marking the item down. :)</p>
<p>@ Xiggi: I heard Gruber’s was best for Math.<br>
So I’m using their math skills to improve it.
So I shouldn’t use Gruber’s because it’s more confusing than anything??/ I’m sorry, but I don’t understand :)</p>