SOLUTION: Pens are sold in packets of 15 pens per packet. The pens are of different colour and 20% are red. a) Show that the probability of a randomly chosen packet of pens containing 3 or

Question 870619: Pens are sold in packets of 15 pens per packet. The pens are of different colour and 20% are red.
a) Show that the probability of a randomly chosen packet of pens containing 3 or more red ones is 0.602.
b) Jack buys 6 packets of pen. Find the probability that at least 5 of the packets contain 3 or more red pens.
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
p (red) = .20, n = 15
a) P(x ≥ 3) = 1 - binomcdf(15, .20, 2)= .602
0r

1 - P(0) + P(x=1) + P(x=2) = 1 - (.035 + .132 + .231) = 1 - .398 = .602
b) p (red) = .20, n = 6
P(x ≤ 5) = 1 - p(x = 6) = 1 - (.2)^6 = 1 - .0001 = .9999

RELATED QUESTIONS
There are 25 red pens, 25 green pens and 25 blue pens in a box. You are blindfolded, how... (answered by fractalier)

There are 25 pens in a packet. 7 of the pens are green. 10 of the pens are black. The... (answered by ikleyn)

There are 648 more blue pens than red pens in stationary shop. After 1/6 of the blue pens (answered by maxitee)

your are purchasing pens and pencils to be sold at the school store. You need a total of... (answered by macston)

There are 10 blue pens, 15 red pens and 3 green pens. .write the ratio of blue pens to... (answered by macston)

There are 12 pens in a pack. 7 of the pens are blue and 5 of the pens are red. Three pens (answered by stanbon)

I'm COMPLETELY confused by this, word problems are my weak spot. :A college bookstore... (answered by jim_thompson5910)

You are purchasing pens and pencils to be sold at the school store. You need a total of... (answered by TimothyLamb)

A college bookstore ordered six boxes of red pens. The store sold 39 red pens last eek... (answered by stanbon,lynnlo)