## Rational expressions: growth of cancer cells

Quadratic equations and inequalities, variation equations, function notation, systems of equations, etc.
ellisw01
Posts: 1
Joined: Sat Dec 17, 2011 5:03 am
Contact:

### Rational expressions: growth of cancer cells

Im having brain poots on this one

In a cancer research lab, you are observing the growth of cancer cells in two specimens, A & B. Specimen A presently has 2160 cells and specimen B has 1200 cells. After recording data for several days, you later determine that the number of cells in specimen A, N(A), is growing ny the formula:

N(A) = 24t^2 + 588t + 2160

where t is the number of days the specimen is in the test environment. Likewise, the data for specimen B indicates that its number of cells, N(B), is

N(B) = 36t^2 + 780t + 1200

a. Write a rational expression and simplify the ratio of N(A) to N(B). Show any intermediate steps.

b. On which day did the number of cancer cells in specimen B overtake that of specimen A?

c. How many cancer cells had developed in specimen B as of the day you calculated in (b)? Show your calculation and write this number using scientific

maggiemagnet
Posts: 358
Joined: Mon Dec 08, 2008 12:32 am
Contact:

### Re: Rational expressions: growth of cancer cells

In a cancer research lab, you are observing the growth of cancer cells in two specimens, A & B. Specimen A presently has 2160 cells and specimen B has 1200 cells. After recording data for several days, you later determine that the number of cells in specimen A, N(A), is growing ny the formula:

N(A) = 24t^2 + 588t + 2160

where t is the number of days the specimen is in the test environment. Likewise, the data for specimen B indicates that its number of cells, N(B), is

N(B) = 36t^2 + 780t + 1200

a. Write a rational expression and simplify the ratio of N(A) to N(B). Show any intermediate steps.
Make the ratio N(A)/N(B) and simplify.
b. On which day did the number of cancer cells in specimen B overtake that of specimen A?
Hint: When the bottom equals the top, the fraction equals 1. Make the equation, and solve.
c. How many cancer cells had developed in specimen B as of the day you calculated in (b)? Show your calculation and write this number using scientific
Plug your value from (b) into N(B) to get the number you need.