math question from the red 10 book

Test Preparation
1

<p>question is on page 431 #8</p>

<p>after jean gave $10 to irene and irene gave $6 to todd, jean had $10 more than irene and $20 more than todd. originally, how much more did jean have than irene and todd?</p>

<p>a. 14 more than irene and 16 more than todd
b. 18 more than ireene and 24 more than todd
c. 18 more than ireene and 26 more than todd
d. 24 more than irene and 26 more than todd
e. 24 more than irene and 36 more than todd</p>

<p>i got this question wrong the the first time going through the section and then went back and analyzed it for a while. answer is (e) but i do not entirely understand the reasoning behind the problem. what i've come up with so far for the answer is that jean has 36 more than todd because if jean hadn't given the 10 to irene.. then todd would have never gotten the 6 (this explains the +6). furthermore.. since jean had given up 10.. when you take this into account 20+10+6 adds up to the 36 more than todd. my problem is that i fail to understand why he has 24 more than irene. jean gave irene 10 (20 so far).. and irene gave up 6 to todd with 4 remainder.. but from my reasoning before this.. i don't see how todd's 6 could've been counted into jean's money had it not been from the 10s' in jean's original stash. need some input on this.. </p>

<p>thanks guys</p>

2

<p>after jean gave $10 to irene and irene gave $6 to todd, jean had $10 more than irene and $20 more than todd. originally, how much more did jean have than irene and todd?</p>

<p>a. 14 more than irene and 16 more than todd
b. 18 more than ireene and 24 more than todd
c. 18 more than ireene and 26 more than todd
d. 24 more than irene and 26 more than todd
e. 24 more than irene and 36 more than todd</p>

<p>Let Jean's original money be x, Irene's be y, and Todd's be z. </p>

<p>x - 10 = (y + 10 - 6) + 10
x - 10 = z + 6 + 20</p>

<p>x - y = 24
x - z = 36</p>

<p>Therefore the answer is e.</p>

3

<p>wow nice! i was attempting this approach but i couldn't form applicable equations.. i ended up just plugging in imaginary numbers for their money and then adding/subtracting from that x__X</p>

4

<p>Just one suggestion:
in questions like this it helps to use the first letters of the names for the variables:
j, i, t
in place of
x, y, z.</p>

5

<p>For future reference, 10RS</a> explanations</p>

6

<p>hm.. i was looking at that website yesterday night and i was unable to match up the page numbers of my red book with the page numbers of the red book on the web.. is there separate versions for the red book?</p>

7

<p>If you have the third edition red book, you'll need to use the numbers in the middle column and do the math to find the exact page number for your questions. The site only has solutions to the first 8 tests in the 3rd edition of 10RS</p>