A civil engineering model for $W$, the weight (in units of 1000 pounds) that a span of a bridge can withstand without sustaining structural damage is normally distributed. Suppose that for a certain span $W\sim N(400, 40^2)$. Suppose further that the weight of cars traveling on the bridge is a random variable with mean $3$ and standard deviation $0.3$. Approximately how many cars would have to be on the bridge span simultaneously to have a probability of structural damage that exceeded $0.1$?

Approximately cars (round to an integer number).