feb long challenge guess it right problem

general
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1

In the problem statement it is given than P/Q, where P and Q are coprime positive integers. You should compute P⋅Q−1 modulo 10^9+7, where Q−1 denotes the multiplicative inverse of Q modulo 10^9+7.
But then how can for 1/5 the answer becomes 400000003.

2

See this https://discuss.codechef.com/questions/145069/guessrt-feb19b

3

multiplicative inverse of 5 modulo 10^9+7 is 400000003