Question 1210203
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Refer to the scratch work that tutor greenestamps has written out.


Note that he mentioned
(40+1)(20+1) = 41*21 = 861
However, it is best to leave it as 41*21
If you're curious how this formula works, then refer to my response on <a href="https://www.algebra.com/algebra/homework/divisibility/Divisibility_and_Prime_Numbers.faq.question.1207622.html">this page</a> 
Additionally you can refer to formula (3) of <a href="https://mathworld.wolfram.com/DivisorFunction.html">this page</a>


A = number of divisors of 20^20
B = number of divisors of 20^20 that do not involve 5 (i.e. involve 2's only)
C = number of divisors of 20^20 that have at least one factor of 5


A = 41*21
B = 41


C = A-B
C = 41*21 - 41
C = 41*(21 - 1)
C = 41*20


D = probability a divisor of 20^20 has at least one factor of 5
D = C/A
D = (41*20)/(41*21)
D = <font color=red>20/21</font> is the final answer in fraction form.


20/21 = 0.95238 = 95.238% approximately
Round this approximate value however needed.
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