Question

For what value of n, 2^n*5^n ends in 5

Answer 1

${2}^{n} \times {5}^{n} = ( {2 \times 5)}^{n} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = {10}^{n} \\ so \: it \: cant \: be \: possible \: for \: any \: value \: of \: n.$