Answer
Given data
Weight of oxygen in tank at sea level $W=1 \mathrm{lb}$
The acceleration due to gravity at sea level $\mathrm{g}_{\mathrm{sea}}=32.174 \frac{\mathrm{ft}}{\mathrm{s}^{2}}$
The acceleration due to gravity at the top of the Everest $g_{\text {top }}=32.082 \frac{\mathrm{ft}}{\mathrm{s}^{2}}$
We know that
Weight $=$ mass $\times$ acceleration due to gravity
$W=m g$
$W_{\text {sealevel }}=m_{\text {sealevel }} \times g_{\text {sea level }}$
And
$W_{\text {top }}=m_{\text {top }} \times g_{\text {top }}$
But mass of any substance remains same anywhere
i.e, $m_{\text {sea level }}=m_{\text {top }}$
$\frac{W_{\text {sea level }}}{g_{\text {sea level }}}=\frac{W_{\text {top }}}{g_{\text {top }}}$
$W_{\text {top }}=\frac{1 \times 32.082}{32.174}$
$W_{\text {top }}=0.997 \mathrm{lb}$
$\therefore$ Weight at the top of Everest $0.997 \mathrm{lb}$
Work Step by Step
Given data
Weight of oxygen in tank at sea level $W=1 \mathrm{lb}$
The acceleration due to gravity at sea level $\mathrm{g}_{\mathrm{sea}}=32.174 \frac{\mathrm{ft}}{\mathrm{s}^{2}}$
The acceleration due to gravity at the top of the Everest $g_{\text {top }}=32.082 \frac{\mathrm{ft}}{\mathrm{s}^{2}}$
We know that
Weight $=$ mass $\times$ acceleration due to gravity
$W=m g$
$W_{\text {sealevel }}=m_{\text {sealevel }} \times g_{\text {sea level }}$
And
$W_{\text {top }}=m_{\text {top }} \times g_{\text {top }}$
But mass of any substance remains same anywhere
i.e, $m_{\text {sea level }}=m_{\text {top }}$
$\frac{W_{\text {sea level }}}{g_{\text {sea level }}}=\frac{W_{\text {top }}}{g_{\text {top }}}$
$W_{\text {top }}=\frac{1 \times 32.082}{32.174}$
$W_{\text {top }}=0.997 \mathrm{lb}$
$\therefore$ Weight at the top of Everest $0.997 \mathrm{lb}$