I seemed to have forgot the formula for how to solve such a question so what I did was take my trust calculator, place the number he'd start with each year, multiply it by 0.2 or the 20%, and subtract that from the number he started with to get how many hairs he would start with in the next year. Then rinse-repeat until I got to 10 years.
Example:
1st year would be 1546 - (1546 x 0.2) = 1546 - 309.2 = 1236.8 hairs to start the 2nd year.
At the end of year 10, my calculation had Mr. Jones left with 166.000486 or ≈166 hairs left on his head. I'd suggest Mr. Jones invested in a women's razor; I've heard their blades are better for shaving yourself bald.
Answer:
two (n = 4, and n = -1)
Step-by-step explanation:
Let's solve it as follows:
First, we can divide out the common factor of 3 from each side, to get:
n(2n-8) = 8 -2n
Next, we expand, and move all the terms over to the right hand side (so that we have 0 on the LHS - as this is how we will want to solve the quadratic equation):
2n^2 - 8n - 8 +2n = 0
2n^2 - 6n - 8 = 0.
We also see we can further simplify by dividing out the factor of 2, to get:
n^2 -3n -4. = 0
Next, as this is a quadratic, the usual next step is to factorise, to get:
(n-4)(n+1) = 0
So we see that n = 4 and n = -1 are the two solutions.
