Peter will have $910 - $40 * x on his account, where x is the number of the weeks. Marla will have $470 - $20 * x.
910 - 40 x = 470 - 20 x
910 - 470 = 40 x - 20 x
440 = 20 x
x = 440 : 20
x = 22
910 - 40 * 22 = 910 - 880 = $30
470 - 20 * 22 = 470 - 440 = $30
Answer: Their accounts will be equal in 22 weeks ( both of them will have $30 ).
Expected Mean, E(X), is obtained by multiplying each pair of

and its

and add up the answers
E(X) = (0×0.7) + (1×0.2) + (2×0.1) = 0.4
The formula to calculate the variance, Var(X), is given by E(X)² - (E(X))²
E(X²) = (0²×0.7) + (1²×0.2) + (2²×0.1) = 0+0.2+0.4 = 0.6
(E(X))² = (0.4)² = 0.16
Var(X) = 0.6 - 0.16 = 0.44
Translating these answers into the context we have
E(Y) = 0.4×500 = $200
Var(Y) = $110
Answer:
The number of seashells he have in his collection all together is <u>140</u>.
Step-by-step explanation:
Given:
Stanley has a collection of seashells. He found 35% of his collection on Florida beaches.
Stanley has 49 seashells from Florida.
Now, to find the number of seashells of his collection altogether.
Let the number of seashells all together be 
Percentage of seashells found on Florida beaches = 35%.
Number of seashells found on Florida beaches = 49.
Now, to get the number of seashells altogether we put an equation:

⇒ 
⇒ 
⇒ 
Dividing both sides by 0.35 we get:
⇒ 
Therefore, the number of seashells he have in his collection all together is 140.
Answer:
Mr. Robins commision rate is 15%.
Step-by-step explanation:
Formula

As given
Mr robbins earns a commission on each airfare he books.
At the end of the day,he had booked $208.60 worth if airfare and earned $31.29.
Here
Part value = $31.29
Total value = $208.60
Put in the formula


Percentage = 15%
Therefore the Mr. Robins commision rate is 15%.