Sumi walks to her office at the rate of 4 miles per hour. If she increases her walking speed by one mile per hour, she would reach her office half an hour earlier than the previous time. What is the distance in miles of her office from her house?

প্রশ্নঃ Sumi walks to her office at the rate of 4 miles per hour. If she increases her walking speed by one mile per hour, she would reach her office half an hour earlier than the previous time. What is the distance in miles of her office from her house?