Finding the rate or time in a word problem on exponential growth or decay

[@victorleon8906]

took me forever to find a video that was quick and helpful, THANK YOU!

[@gangstashuckle]

literally wasted 30 min trying to learn this from a dumb text book thankyou

[@shielacee1518]

Hi how did you get 3r ? Needed reply ASAP

[@JennaVanSickle]

The equation in the second example is A=Pe^(rt) with t=time=3 years, which means you need to plug in 3 for t. That's how you get 3r in the exponent.

[@HiHi-kc8ej]

It’s wrongggg. I worked backwards to see if it was right by plugging in. Here is my proof: 3150=2000*.15^3. So .15^3 is .003375. You times that by 2000 and get 6.75. That is not 3150. I am not trying to hate u am just trying to tell people this is a mistake.

[@JennaVanSickle]

You have forgotten about the e in this problem. The formula we are using is A=Pe^(rt), so you have skipped the e part entirely when checking the answer. As I said at the end, the answer is really .1514, so if you are plugging it back in, best not to round too much, so 2000e^(.1514*3)=3149.826, which rounds back to 3150, so it is correct. I hope that makes sense, and thanks for checking!

[@xaadrianaax]

thank you!!