Which one of the following will completely divide $$5^{71} + 5^{72} + 5^{73}$$ ?
Expression : $$5^{71} + 5^{72} + 5^{73}$$
= $$5^{71} (1 + 5 + 5^2) = 5^{71} \times 31$$
= $$5^{70} \times 155$$
Clearly, above expression is easily divisible by 155.
=> Ans - (C)
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