The mean of 6 numbers is 40. If the number 10 is removed from the list, what is the mean of the remaining 5 numbers?

The original total is $6 \times 40 = 240$. Removing the number 10 leaves $240 - 10 = 230$ spread over 5 numbers, so the new mean is $\frac{230}{5} = 46$, choice A. The mean rises because the removed number, 10, was far below the mean of 40. Choice B (30) would result from subtracting 10 from the mean directly. Choice C (38) comes from $\frac{240 - 10}{6}$, dividing by the old count. Choice D (50) is wrong because 50 would require removing a value of $-10$, not 10. Use totals, not means.