In 2009 the life expectancy is about 80 life expectancy gains 5.7 years every decade. From 2009 in how many years would humanity achieve a life expectancy of 120 years

  about 70 years

Step-by-step explanation:

Life expectancy (e) improves by 5.7 years every 10 years, so 5.7/10 = 0.57 years per year. For t years after 2009, it can be modeled by ...

  e = 0.57t +80

We want to find when that is 120:

  120 = 0.57t +80

  40 = 0.57t

  40/0.57 = t ≈ 70.2

About 70 years from 2009, humanity may achieve a life expectancy of 120 years.

c. 27 units.

step-by-step explanation:

we are told that in circle a, ∠bae ≅ ∠dae.

we can see from our given diagram that in and ;

, as these are radii of our given circle.

therefore, by sas congruence postulate.

hence, side be will be equal to side de as corresponding parts of congruent triangles are congruent. so we can set an equation to find the value of x as:

now let us substitute x=17 in the expression for the length of be.

therefore, length of be will be 27 units and option c is the correct choice.