Alex competes in 100 m wheelchair races. He calculates the information
below using his last 4 race times.
His minimum race time was 18.9 s.
The range of his race times was 5.2 s.
The median of his race times was 22.3 s.
The mode of his race times was 24.1 s.
If Alex includes a new race time of 24.9 s in his calculations, how much will
the mean change by?
Give your answer in seconds (s).