Question

Chris drove 250 miles using 9 gallons of gas. At this rate, how many gallons of gas would he need to drive 275 miles?

Answer 1

Chris would need `9.9` gallons of gas.

Explanation:

To drive `250` miles, Chris uses `9` gallons of gas

Hence to drive `1` mile he uses `9/250` gallons of gas

and to drive `275` mile he uses `9/250xx275` gallons of gas

i.e `9/(10cancel250)xx11cancel275` - dividng by `25`

or `(9xx11)/10=99/10=9.90` gallons.