Ken is working this summer as part of a crew on a farm. He earned $8 per hour for the first 10 hours for the rest of the week. Ken saves 90% of his earnings from each week. What is the least number of hours he must work the rest of the week to save at least $270?
⇒90100×x=$270
⇒90x=$270×100=$27000
⇒x=$2700090
⇒x=$300
So, number of more hours Ken need to work =remaining amount need to be savedhourly rate
=$220$10/hour=22hours