Answer
$1218.84\space N$
Work Step by Step
Please see the image first.
Let's apply equation $F=ma$ to Martian.
$\uparrow F=ma$
$R-84g=84\space kg\times10.8\space m/s^{2}$
$R-84kg\times3.71\space m/s^{2}=907.2\space N$
$R=907.2\space N+311.64\space N$
$R=1218.84\space N$
