If $\text{F}=\left(60\hat{i}+15\hat{j}-3\hat{k}\right) \text{N}$ and $\mathit{\text{v}}=\left(2\hat{i}-4\hat{j}+5\hat{k}\right) \text{m}/\text{s,}$ then instantaneous power is 

Given, force  $\text{f}=\left(60+15-3\right)\text{\hspace{0.17em}N}$
Velocity,  $\text{V}=\left(2-4+5\right)\text{m}/\text{s}$
Instantaneous power, P = F . v
=  $\left(60+15-3\right).\left(2-4+5\right)$
$= 120 – 60 – 15 = 45 watt$