Given that 92% of athletes have PBs of more than t seconds, this implies that 8% have PBs less than t seconds. In a standard normal distribution, this corresponds to a z-score of approximately -1.406.

Using the standardization formula:

\(z = \frac{t - \mu}{\sigma}\)

where \(\mu = 49.2\) and \(\sigma = 2.8\), we have:

\(\frac{t - 49.2}{2.8} = -1.406\)

Solving for \(t\):

\(t - 49.2 = -1.406 \times 2.8\)

\(t - 49.2 = -3.9368\)

\(t = 49.2 - 3.9368\)

\(t = 45.2632\)

Rounding to one decimal place, \(t = 45.3\).