You need to know the distribution's mean and standard deviation.
Transforming to the standard normal distribution, and letting
denote the standard deviation,
The z-score corresponding to this probability is approximately
, so you have
C = # of carpenter hrs , b = # of blacksmith hrs
c + b = 30...c = 30 - b
20c + 25b = 690
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
-20b + 25b = 690 - 600
5b = 90
b = 90/5
b = 18 <== hrs worked as blacksmith
c + b = 30
c + 18 = 30
c = 30 - 18
c = 12 <== hrs worked as carpenter
For 1.30 you will shade in one full grid because that equals 1 and also shade in 3 coloms on the next grid which equals .30.
Then shade in 5 coloms and 1 single block on the the next grid which will equal .51 after
1)
= 12zy^2
2)
= 12^8
= <span>429,981,696
</span>
3)
= x^21
The 8 would be in the hundredths place. I hope this helped. :) Brainliest answer? :)
