Answer
a) 590 steps
b) $18^{\circ}C$
Work Step by Step
(a) We can find the required number of steps as follows:
The energy consumed by the brain is:
$E=Pt$
$\implies E=(22)(3600)=79.2KJ$
The potential energy gained while climbing one step is
$E=mgh$
$E=(65)(9.81)(0.21)$
$E=134J/step$
Now $number \space of \space steps=\frac{79,200J}{134J/step}=590steps$
(b) We can find the required temperature as
$\Delta T=\frac{Q}{mC}$
We plug in the known values to obtain:
$\Delta T=\frac{79200}{(0.77\times 1.4)(4186)}=18^{\circ}C$