22 quarters= $5.50
10 dimes= $1.00
$5.50 + $1.00 = $6.50
I just did trial and error. I started with 20 quarters and made changes until it worked.
Answer:
p(on schedule) ≈ 0.7755
Step-by-step explanation:
A suitable probability calculator can show you this answer.
_____
The z-values corresponding to the build time limits are ...
z = (37.5 -45)/6.75 ≈ -1.1111
z = (54 -45)/6.75 ≈ 1.3333
You can look these up in a suitable CDF table and find the difference between the values you find. That will be about ...
0.90879 -0.13326 = 0.77553
The probability assembly will stay on schedule is about 78%.
400,000 60,000
0,000
000
50
3
(1/4)^-2 - (5^0 x 2) x 1^-1 =
(4/1)^2 - (1 x 2) x 1 = 16-2 = 14
If you raise something to the power of -2, swap numerator and denominator and remove the minus.
So (1/4)^-2 = 4^2 = 16
Also 1^-1 is just 1, not -1.