Answer:
0.8753
Step-by-step explanation:
Calculate the probability that your job will be ready before 10.01 am
Here, the parameter of an Exponential is E(X)=12
Now, to calculate the third job probability, it follows Poisson Distribution with parameter 1/λ
Therefore, E(Y) =1/12
Here, The third job will be ready for 10:01 AM, then E(Y)=61/12
Therefore, the required probability is

=1- POISSON(3,5,true)
=1-0.1246
=0.8753
Answer:
The amount the school pays is £32.40
Step-by-step explanation:
The cost of each pen = 15 pence
The cost of each ruler = 20 pence
The number of pens bought by the school = 150
The number of rulers bought by the school = 90
The cost reduction (discount) on the items bought = 1/5
Therefore, we have;
The total cost of the pens bought by the school = 150 × 15 = 2250 = £22.50
The total cost of the rulers bought by the school = 90 × 20 = 1800 = £18.00
The total cost of the writing materials (rulers and pens) bought by the school = £22.50 + £18.00 = £40.50
The discount = 1/5 total cost reduction = 1/5×£40.50 = $8.10
The amount the school pays = The total cost of the writing materials - The discount
The amount the school pays = £40.50 - $8.10 = £32.40
The amount the school pays = £32.40.
N - Nicholes money
M - Marys money
(1) N + M = 4800 ⇒ N = 4800 - M
(2) N - 800 = M - 2/5M ⇒ N - 800 = 3/5M
subtitute (1) to (2)
4800 - M - 800 = 3/5M
4000 - M = 3/5M
-M - 3/5M = -4000
-8/5M = -4000 |multiply both sides by (-5/8)
M = 2500
subtitute the value of M to (1)
N = 4800 - 2500
N = 2300
Answer: Mary had at first $2500. (Nichole: $2300).