The total number of two digit numbers ‘n’,
Question:

The total number of two digit numbers ‘n’, such that $3^{n}+7^{n}$ is a multiple of 10 , is________.

Solution:

for $3^{n}+7^{n}$ to be divisible by 10

$\mathrm{n}$ can be any odd number

$\therefore$ Number of odd two digit numbers $=45$

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