<p>Pg. 838 #7 in blue book
if y is inversely proportional to x and y=15 when x=5 what is the value of y when x=25?</p>
<p>a) 1/5
b) 1/3
c) 3
d) 5
e) 75</p>
<p>i'm pretty sure it's a simple problem...</p>
<p>y = a/x (equ. for inversely proportional)</p>
<p>15 = a/5 (solve for A)</p>
<p>a = 75.....thus......</p>
<p>y = 75/25 (plug A into the equ.)
y = 3</p>
<p>i believe this is the correct answer.</p>
<p>c</p>
<p>5<em>15=25</em>y
75=25y
y=3</p>
<p>hope this helps</p>
<p>wow, one minute slower...</p>
<p>y = k/x
15 = k/5
k = 75
y=75/x
y=75/25
y=3</p>
<p>lol three answers within 3 minutes</p>
<p>thank you!</p>
<p>how about pg. 860 #18...anyone have a NEW solution to it? a new method?</p>
<p>pg. 860 #20
if k is a positive integer, which of teh following must represent an even integer that is twice the value of an odd integer?
a) 2k
b) 2k+3
c)2k+4
d)4k+1
e)4k+2</p>
<p>thanks!!! you guys are amazing.</p>
<p>this was posted in another thread somewhere</p>
<p>840 / 7.
If x goes up from 5 to 25 (5 times), then y should go down 5 times:
15/5 = 3 - that's your new y.</p>