Len estimated the sum of 16.23, 215.7, and 110.3 by rounding each number to the nearest whole. What was Len's estimate and what is the actual sum of the numbers? please, please hurry

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.