Exponential Growth in Species A and B: Solving for Initial Grams

[jackleyt]

Homework Statement

Species A doubles every 2 hours and initially there are 6 grams. Species B doubles every 5 hours and initially there are 14 grams.

Homework Equations

The Attempt at a Solution

I've tried graphing this, but I don't think I have the right equations down. I don't know how to form the equations so I can solve the problem.

 

[whybother]

In general for 'doubling time' problems, we have a simple formula

$$N = N_0 \times 2^{t \over T}$$

where N is the number of bacteria after t minutes and T is the time in minutes that it takes to double.

So if that's the relevant equation, attempting a solution should be possible.

EDIT: Although I don't actually know what your question is.

 

[n!kofeyn]

I don't know how to form the equations so I can solve the problem.

You didn't even say what the problem is.

 

[jackleyt]

*How long until the species have the same mass? Sorry.

 

[whybother]

*How long until the species have the same mass? Sorry.

Okay so you know the equations by which they grow for each of them, and then you set them equal to each other and solve for t.