Consider thr following limit order book.

$\backslash$table$[[$Limit Buy Orders,Limit Sell Orders$],[$Price$,$Size,Price,Size$],[84\mathrm{.}77,200,84\mathrm{.}79,100],[84\mathrm{.}76,100,84\mathrm{.}80,300],[84\mathrm{.}75,400,85\mathrm{.}70,700]]$

If you submitted a market sell order for $400$ shares, how much would you receive? If someone sent a market sell order immediately after you $($before any new orders entered the order book$)$ at what price would they sell?