00:01
So i'm trusting that parts a and b are done correctly.
00:04
I haven't worked it out, but if you're going to trust that the formula is this, i can help you get the final answer.
00:17
Just double -checking and write it down, 28 -76 -820t.
00:23
And the whole thought process on part c is that you are setting the equation equal to 400 because all of our units here are in millions.
00:36
So at this point, what you have to do is divide this 90 over and feel free to reduce that number or just leave it as is, but you'd be left with 40 over 9.
00:48
Let me just rewrite this e to the 0 .0287682.
00:53
Let me drop those zeros as well.
00:55
Because my next step will be two natural log both sides.
00:59
And the reason for that is it cancels out the e, and now to solve for t, i just need to divide that number over.
01:08
Now, i am rounding this answer.
01:10
So if you have a slightly different answer, that might be y...