This is all I got. Hope this helps:
Answer/Step-by-step Explanation:
Given:
a = no. of DVDs
b = no. of CDs
Total cost ($) for DVDs and CDs = 
a. The cost for 1 DVD = 2.5(a) = 2.5(1) = $2.5
The cost for 1 CD = 2(b) = 2(1) = $2
b. Total cost for 4 DVDs and 4 CDs:
Substitute a = 4, and b = 4 into the equation.


Total cost for 4 DVDs and 4 CDs = $18
c. To find out if $20 would be enough to buy 6 DVDs and 3 CDs, substitute a = 6, and b = 3 into the equation. Solve for the total cost to see if it equals $20 or is less than $20. If it's greater than $20, then it won't be enough.


6 DVDs and 3 CDs cost more than $20, therefore, $20 is not enough.
Answer:
67
Step-by-step explanation:
Answer: 3/8
Explanation: To subtract unlike fractions such as 5/8 - 1/4, first find a common denominator. The common denominator of 8 and 4 will be the least common multiple of 8 and 4 which is 8.
Notice that our first fraction already has 8 in the denominator so it stays the same. To get 8 in the denominator of 1/4, we multiply the numerator and denominator by 2 to get 2/8.
Now we have 5/8 - 2/8.
To subtract like fractions, we simply subtract the numerators to get 3 and keep our denominator of 8 and we have 3/8.
Since 3/8 is in lowest terms, it's our final answer.
Therefore, 5/8 - 1/4 = 3/8.
The Poisson probability distribution function is

where
μ = mean number of successes
x = actual or expected number of successes
Given:
μ = 13
x = 5
Therefore the probability that x=5 is
P(x = 5) = (e⁻¹³*13⁵)/5!
= 0.8392/120
= 0.006994
= 0.0070 (to 4 dec. places)
Answer: 0.0070 (to 4 decimal places)
It is interesting to observe P(x) as x varies, as in the graph shown below.