## anonymous 5 years ago f(t)=1.8(1.452)^t t=0 correspond to year2004. In what year will sales reach 20 billion?

1. anonymous

you are trying to solve $20=1.8(1.452)^t$ for t. divide by 1.8 $\frac{20}{1.8}=(1.452)^t$ take the log of both sides $\ln(\frac{20}{1.8})=\ln((1.452)^t)=t\ln(1.452)$

2. anonymous

solve for t: $t=\frac{\ln(\frac{20}{1.8})}{\ln(1.452)}$

3. anonymous

thats what i got, but the answer would be 6.5 so the year 2010,

4. anonymous

i get 6.4 so 6.4 years after 2004 is 2010.4 of there abouts.

5. anonymous

but the question before asked what are sales in 2010 and my answer was 16.9.....not 20. im confused

6. anonymous

maybe be safe and say by 2011

7. anonymous

i guess the additional .5 counts! let me try it.

8. anonymous

thanks so much

9. anonymous

welcome!