The loudness $L(x),$ measured in decibels $(d B),$ of a sound of intensity $x,$ measured in wans per square meter, is defined as $L(x)=10 \log \frac{x}{I_{0}},$ where $I_{0}=10^{-12}$ watt per square meter is the least intense sound that a human ear can detect. Determine the loudness, in decibels, of each of the following sounds.
Diesel truck traveling 40 miles per hour 50 feet away: intensity
10 times that of a passenger car traveling 50 miles per hour
50 feet away, whose loudness is 70 decibels.