Please see attached:
Probability is approximately: 0.256
n(A) = 26
Solution:
Let us first define the cardinal number of the set.
Cardinal number of the set:
The number of distinct elements in a finite set is called its cardinal number. It is denoted as n(A).
Given set: A = {a, b, c, .... z}
We know that, there are 26 elements in the alphabet "a to z".
Number of elements in the set A = 26
Hence n(A) = 26.
7/100 = 0.07
0.07 * 12.5 = 0.88
20/100 = 0.2
0.2 * 12.5 = 2.5
2.5 + 0.88 = 3.38
3.38 + 12.50 = 15.88
You spend a total of $15.88.