Dividing of cells a sample problems of geometric
progression. Given that the intial number of cells is 40, then it will double
every 20 minutes. Within 7 hours the cells will divide into w by 21 times. So the
number of cells after 7 hrs is 4,194,040 cells.
There are 5280 feet in a mile:
5280ft/mi
When using proportions to solve for unknown quantities, you need to keep the same units on the same side. This means keep "ft" on the top side and "mi" on the bottom side.
I would go with the second choice.
Given:
A line passes through the points (2,-1) and (1,-5).
To find:
The equation of the line.
Solution:
If a line passes through the two points, then the equation of the line is
The line passes through the points (2,-1) and (1,-5). So, the equation of the line is
Using distributive property, we get
Subtract 1 from both sides.
Therefore, the correct option is B.