Fifty numerical data points have a mean of 20. If each data point is doubled and combined with the original data points to form 100 data points, what is the numerical average of the combined data?

50(20) = 1000

When each data point is doubled we have 1000 * 2 = 2000

So

[ 1000 + 2000] / 50 =

3000 / 100 =

30 = new average