Based on data from the U.S. Census Bureau, an approximate family income distribution for the United States is given by the function

where x is the annual income in units of $10,000, with 0 ≤ x ≤10. For example, x = 0.5 represents an annual family income of $5000. The percent of the families with an income in a given range can be found by integrating this function over that range. Find the percentage of families with an income between $25,000 and $50,000.

f(x) = 0.0353x 0.541x +3.78x + 4.29,