First problem: I believe YW: 34
ZX: 17
VX: 34. I have a pic attached but it probably doesn’t make much sense :)
Answer:
The probability that a manufactured ball will be rejected is 0.99, to two decimal places.
Step-by-step explanation:
The mean weight is 16 Ibs. The standard deviation of the weights of all manufactured balls from the mean weight is 25. The distribution is normal. With a standard deviation this large, it is already obvious that there is a high probability of producing or having rejected balls. The weights of the balls produced here ranges from (16-25)Ibs to (16+25)Ibs.
That's -9Ibs to 41Ibs.
The minimum permissible weight is 15.68. Any ball with a lesser weight gets kicked out!
So the distance or difference between this figure and the mean is (16-15.68) = 0.32
So the probability of obtaining less than 15.68Ibs or the probability of having balls between the lower boundary of -9Ibs and 15.68 is:
25-0.32 = 24.68
24.68 ÷ 25 = 0.9872 ~ 0.99 to two decimal places.
Expand the left hand side:
Simplify the left hand side:
Subtract 79.99 from both side:
Divide both sides by 17:
So, he must invite less than 7 friend to the party.
15 is 48 and 16 will be tricky!
