We have 12 girls and we can pick any three.....and we have 10 boys and we can pick any three

So  C(12,3) * C(10,3)  = 26,400 ways

12012₃  = 1(3)^4 + 2(3)^3 + 0(3)^2 + 1(3)^1 + 2(3)^0   =  81 + 54 + 0 + 3 + 2 =  140₁₀

0.050505...... =  5/99 *1.8 =  [5/99] * [18/10]  = [5/10]*[18/99] = [ 1/2]*[18/99] = [9/99] = 1/11

You ended up with a shiny red car

I ended up with only one star  !!!!

This ain't fair....might I opine

I'm having beer.......

You're having wine  !!!!

How did you end up with more stars than me when I answered the question ??????

P(t) =  1,150,000(1 – e–0.03t)

60% of the population = 690,000  ...... so we have....

690,000 =   1,150,000(1 – e–0.03t)        divide both sides by 1,150,000

.60  = (1 - e^(-0.03t))   rearrange

.40  = e^(-0.03t)     take the ln of each side

ln .40  = ln e^(-0.03t)   and we can write

ln .40  = -.0.03t       divide both sides by -0.03

ln .40 / -0.03 = t = about 31 days

Well......I'm waiting for my "Gold Star"  for that one  !!!!

I'm assuming the "star" can be fashioned out of a pentagon inscribed in a circle having a radius of 1.  And the center of this circle is located at (0, 0).

I'm also assuming that the "top" corner (vertex) of the star is located at (0,1)

Then.......proceeding clockwise, the next corner (vertex)  is located at (cos (18), sin (18))  = about (.951, .309)

And the next corner is located at (cos (306), sin (306))  = about (.588, -.809)

And by symmetry, the final two corner points are located at  (-.588, -.809)  and (-.951, .309)

Very nice, Alan   !!!!

12/15 = 20/b      cross-multiply

12b = 15*20

12b = 300        divide both sides by 12

b = 25