# Simple Algebra - solving for R

• Jan 18th 2011, 10:14 AM
killasnake
Simple Algebra - solving for R
Its been awhile since I took a math class, I was reviewing this question but I do not understand where the \$\displaystyle 4 \$came from. I understand the rest but I am clueless about that\$\displaystyle 4\$

\$\displaystyle 4000=1000\$ x \$\displaystyle (1+r)^5\$
\$\displaystyle (1+r)^5=4\$
\$\displaystyle (1+r)=4.0\$^(1/5)\$\displaystyle =1.32\$
\$\displaystyle r=.32\$

This came from my math book.
• Jan 18th 2011, 10:25 AM
Quacky
Quote:

Originally Posted by killasnake
Its been awhile since I took a math class, I was reviewing this question but I do not understand where the \$\displaystyle 4 \$came from. I understand the rest but I am clueless about that\$\displaystyle 4\$

\$\displaystyle 4000=1000\$ x \$\displaystyle (1+r)^5\$
Divide both sides of the equation by 1000.
\$\displaystyle (1+r)^5=4\$
\$\displaystyle (1+r)=4.0\$^(1/5)\$\displaystyle =1.32\$
\$\displaystyle r=.32\$

This came from my math book.

~Quacky.
• Jan 18th 2011, 11:29 AM
Wilmer
If ab = x, then a = x/b OR b = x/a (ab means a times b)