Question

how many prime numbers less that 100 and greater than 3 are of the

form:4x+1 , 5y-1​

Answer 1

Answer:

jyehehehejebekjdhddhehdhndns

Answer 2

Let the number be N.

So N = 4x + 1 = 5y - 1

= X = 5y-2/4

y = 2 satisfies the equation. So minimum number satisfies both the equations is 9 and general format of the numbers which satisfies the equation = k. LCM (4, 5) + 9 = 20k + 9.

Now by putting values 1, 2, 3 . . . . for k, we get 29, 49, 69, 89.

Of which only 29, 89 are prime

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