A. 55 b. 70 c. 110 d. 125

A company with n employees publishes an internal calendar, where each day lists the employees having a birthday that day. What i

lutik1710 [3]

Answer: $1-(\frac{364}{365})^n$

Step-by-step explanation:

Binomial probability formula :-

$P(x)=^nC_xp^x(1-p)^x$ , where P(x) is the probability of getting success in x trials, n is the total number of trials and p is the probability of getting success in each trial.

We assume that the total number of days in a particular year are 365.

Then , the probability for each employee to have birthday on a certain day :

$p=\dfrac{1}{365}$

Given : The number of employee in the company = n

Then, the probability there is at least one day in a year when nobody has a birthday is given by :-

$P(x\geq1)=1-P(x$

Hence, the probability there is at least one day in a year when nobody has a birthday = $1-(\frac{364}{365})^n$

5 0

3 years ago

Solve. X-9 = 12 .....

Lelechka [254]

Answer:

x=21

Step-by-step explanation:

x=9+12 x=21

5 0

2 years ago

Read 2 more answers

An aeroplane X whose average speed is 50°km/hr leaves kano airport at 7.00am and travels for 2 hours on a bearing 050°. It then

Zigmanuir [339]

Answer:

(a)123 km/hr

(b)39 degrees

Step-by-step explanation:

Plane X with an average speed of 50km/hr travels for 2 hours from P (Kano Airport) to point Q in the diagram.

Distance = Speed X Time

Therefore: PQ =50km/hr X 2 hr =100 km

It moves from Point Q at 9.00 am and arrives at the airstrip A by 11.30am.

Distance, QA=50km/hr X 2.5 hr =125 km

Using alternate angles in the diagram:

$\angle Q=110^\circ$

(a)First, we calculate the distance traveled, PA by plane Y.

Using Cosine rule

$q^2=p^2+a^2-2pa\cos Q\\q^2=100^2+125^2-2(100)(125)\cos 110^\circ\\q^2=34175.50\\q=184.87$ km$

SInce aeroplane Y leaves kano airport at 10.00am and arrives at 11.30am

Time taken =1.5 hour

Therefore:

Average Speed of Y

$=184.87 \div 1.5\\=123.25$ km/hr\\\approx 123$ km/hr (correct to three significant figures)$

(b)Flight Direction of Y

Using Law of Sines

$\dfrac{p}{\sin P} =\dfrac{q}{\sin Q}\\\dfrac{125}{\sin P} =\dfrac{184.87}{\sin 110}\\123 \times \sin P=125 \times \sin 110\\\sin P=(125 \times \sin 110) \div 184.87\\P=\arcsin [(125 \times \sin 110) \div 184.87]\\P=39^\circ $ (to the nearest degree)$