500
Four retired friends meet in the park each day to play chess. The mode of their ages is 58. The median of their ages is 62. Ronald, the most senior member of the group, turned 70 on his last birthday. What is the mean of their ages?
The mean is 63.
The mode is 58 and the median is 62, so the youngest two are 58. The second oldest must be 66, because 62 is half way between 58 and 66. The friends are 58, 58, 66, and 70, which totals to 252, and 252/4=63.