Help with sat math level 2 Princeton

Test Preparation
1

<p>A shipment of 3200 items is divided into two portions so that the difference between their portions is one half their average. What is the ratio of the smaller to the larger portion?
A. 1:2
B. 1:3
C. 2:5
D. 3:5
E. 5:8</p>

<p>I got b. Apparently, the answer is D. Could someone pleaSe explain this to me?</p>

<p>Sent from my iPod touch using CC</p>

2

<p>You have 2 portions totaling 3200 so the average is 1600. One-half that average is 800. Thus one portion has 800 fewer items than the other. That means to total 3200, one portion is 1200 and the other 2000 and 1200/2000 is 3/5</p>

3

<p>Wow… I kept thinking the average was 3200 for some reason. Stupid me. Thank you (:</p>

<p>Sent from my iPod touch using CC</p>

4

<p>a+b=3200</p>

<p>a-b= (a+b)/4</p>

<p>4(a-b)=a+b</p>

<p>4a-4b=a+b</p>

<p>3a=5b</p>

<p>a=5b/3</p>

<p>5b/3 + b = 3200</p>

<p>8/3(b) = 3200</p>

<p>b=1200</p>

<p>a + 1200= 3200</p>

<p>a=2000</p>

<p>1200 : 2000 = 3/5</p>

<p>The answer is D.</p>

5

<p>d’oh!!! you figured it out while i was typing the solution. lol</p>