There are 100 values in the set The median is 90 the mean is 95 Increase the highest value in the data set by 200 Now what are the median and the mean of the data set?

The median is the middle value (or mean of the two middle values if there are an even number of values) and so is unaffected by an increase in the highest data value. It is still 90.

The mean was 95, so the total for the data set was 95x100 = 9500. If the highest data value is increased by 200, the data set total is also increased by 200, giving a new data set total of 9500 + 200 = 9700, so the new mean is 9700/100 = 97.