Answer:
Five
Explanation:
There are 9 two-digit numbers with a units digit of 7:
17, 27, 37, 47, 57, 67, 77, 87, 97
Of these, 4 are composite numbers:
27 = 3³
57 = 3×19
77 = 7×11
87 = 3×29
The remaining 5 are prime numbers:
17, 37, 47, 67, 97
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