- A9 and 12
- B10 and 14
- C9 and 10
- D15 and 20
Step-by-Step Solution
and have no common factor except 1, so they are co-prime. The other pairs share a common factor (3, 2 or 5).
Answer: C) 9 and 10
Two students in Kochi pick numbers. One picks 8, the other picks 25. They notice that 8 and 25 are co-prime even though both are composite.
Which other pair of composite numbers is also co-prime?
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