Question

Pre-calculus word problem 1/3

Answer 1

just plug in 20/100 for p
and T=5730

Answer 2

that is a lot of necessary words i think
if the half life is \(5730\) then you can solve by setting \[\left(\frac{1}{2}\right)^{\frac{t}{5370}}=0.2\] and solve for \(t\)

Answer 3

to find time elapsed

Answer 4

oh even easier !

Answer 5

Wait so what would the equation be, when the values are plugged in?

Answer 6

if you have Ti calculator you can do log base 2

Answer 7

you can substitute T and P with 5730 and .2

Answer 8

course you still have to solve it using the change of base formula

Answer 9

t=-5730log_2(0.2)

Answer 10

or change the formula yeah

Answer 11

change of base
log_b(a)=lna / lnb base b to base e

Answer 12

So t=13304.6479837 ?

Answer 13

hmm seems fine to me!

Answer 14

Ok, thank you!

Answer 15

Wait so how would I word it?

Answer 16

that should be in seconds i suppose

Answer 17

just need to write it will take "what the answer you found" for carbon-14 to decay to 20%

Answer 18

ok!

Answer 19

how much will that be in hours?

Answer 20

13304.6479837 seconds, so how many hours? hmm...hold on

Answer 21

3.695735551027778 hours? lol

Answer 22

u divided by 3600

Answer 23

nearly 4 hours

Answer 24

that has nothing to do with the question, i'm just interested to see what 's going on

Answer 25

So the answer is: "It will take 13304.6479837 seconds for carbon-14 to decay to 20%." ??

Answer 26

yes correct! you don't need to convert
as the s is the standard unit

Answer 27

Ok, thanks! :) Can you help me with two more word problems like this?

Answer 28

let's see, i suck at word problems haha