Markov bound on total exponential weight

One hundred items have independent weights, each exponentially distributed with mean $250$ grams. Let $T$ be their combined weight. What upper bound does Markov's inequality give for $\mathbb{P}[T>26000]$?

$\tfrac{25}{26}$. Markov's inequality for a non-negative variable gives $\mathbb{P}[T>a]\le\mathbb{E}[T]/a$. Here $\mathbb{E}[T]=100\cdot250=25000$, so the bound is $\tfrac{25000}{26000}=\tfrac{25}{26}$.