Question

Erin and Karissa are 114 miles apart, traveling towards each other. If Karissa travels 12 mph and Erin travels 7 mph how long until they meet?

Answer 1

`They\ will\ meet\ after\ 5.43\ hours\ or\ 5\ hours\ 25.8\ minutes.`

Explanation:

`Let\ they\ meet\ after\ x\ hours.`

Distance covered by Karissa:

`Speed=12\ mph\\\\Time=x\ hours\\\\Distance=speed* time\\\\Distance=12* x\\\\Distance=12x`

Distance covered by Erin:

`Speed=9\ mph\\\\Time=x\ hours\\\\Distance=speed* time\\\\Distance=9* x\\\\Distance=9x`

Total distance:

`Total\ distance=114\ miles\\\\Total\ distance=Distance\ covered\ by\ Karissa+Distance\ covered\ by\ Erin\\\\Total\ distance=12x+9x\\\\12x+9x=114\\\\21x=114\\\\x=(114)/(21)\\\\x=5.43\ hours`