Answer:
If this trend continues, life expectancy will be 73 years in the year 1990
Step-by-step explanation:
Hi
first of all, we build a model with the knowns of the problem, so we have
in years after 1900, then we have
as we isolate for
,
, finally, we obtain that the birth year which the average life expectancy will be 73 years is 1990
The rule of the volume of the rectangular prism is

L is the length
W is the width
H is the height
From the attached picture we can see
L = (2x - 3)
W = (x + 1)
H = (3x + 4)
We will substitute them in the rule above

We will multiply the first 2 brackets, then multiply the answer by the 3rd bracket

Multiply this answer by the 3rd bracket

Then the volume of the prism is

The answer is the 2nd choice
Answer:

Step-by-step explanation:
Let the fraction be
.
That would mean:
(1) x+y = 19
&
(2) y+8 = 2x or 2x = y+8
In order to use substitution, we multiply equation by 2:
(3) 2x+2y = 38
Then we substitute equation (2) into (3):
y+8 + 2y = 38
3y + 8 = 38
3y = 30
y = 10
Substitute this into equation (1)
x + 10 = 19
x = 9
Therefore the fraction would be:
