The bike in the picture is a Trek 7000 mountain bike. It has either 21 or 24 speeds (number of cogs int he back X number of chainrings in the front). It was a decent quality mountain bike, TIG welded frame made in (I think) Taiwan. Probably sold for between $800 - $1000 BITD. Probably circa 1996 or so.

Around 1995 - 96, the style of brakes that came on most mountain bikes changed from a centre-pull cantilever brake (where a bare run of cable forms a triangle above the brakes) to 'V' brakes (where the cable and housing run all the way to one arm of the brake and the inner cable runs from one arm to the other). THe picture shows a bike with cantilever brakes, which means it is likely from ~95 or before.