Let A ={x ∈ R:[x+3]+[x+4] ≤ 3}, B ={x ∈ R: 3^x(Σ_r=1^∞ 3/10^r)^x-3<3^-3 x}, where [ t ] denotes greatest integer function. Then,

Let $\displaystyle \mathrm{A}=\{x \in \mathbb{R}:[x+3]+[x+4] \leq 3\}$, $\displaystyle \mathrm{B}=\left\{x \in \mathbb{R}: 3^x\left(\sum_{r=1}^{\infty} \frac{3}{10^r}\right)^{x-3}<3^{-3 x}\right\}$, where $\displaystyle [\mathrm{t}]$ denotes greatest integer function. Then,