Answer:
50 years
Step-by-step explanation:
Let x be the number of decades after 2009 and y be the life expectancy ( in years ) after x decades,
∵ life expectancy gains 5.7 years every decade,
If In 2009, the life expectancy is about 80 years.
So, the life expectancy after x decades,
y = 80 + 5.7x
If y = 110 years,
∴ 110 = 80 + 5.7x
⇒ 110 - 80 = 5.7x
⇒ 30 = 5.7x
⇒ x = [tex]\frac{30}{5.7}[/tex] = 5.26315789474 ≈ 5
Hence, after 5 decades or 50 years since 2009 the life expectancy would be 110 years.
