Potato paradox

The potato paradox is a product resulting from the following riddle:

The potatoes weigh just 50 kilograms ( 49 kg water and 1 kg of dry matter ). In MathWorld this circumstance is called a potato paradox, the name is also used for the Giffen paradox, which should have been considered during the Great Famine in Ireland for potatoes.

Explanation

The proportion of dry matter before drying one percent and two percent after drying has, therefore doubled. The actual dry matter is still the same, so the total mass is halved.

Discussion

The result is counter-intuitive at first glance, especially since the water content is reduced only by one percent. The miscarriage of justice is promoted sent, by saying the task, the potatoes are dried in the sun "something" one. When exact recalculation it can also lead to incorrect results that far exceed 50 kilograms. If it is not considered that the percentages refer to different basic values ​​, the potatoes seem to weigh 98 kg, as two percent of the original water mass are two kilograms. Another error arises when proportionality between the ratio and the mass is assumed. For, if 99 percent of a base value 100 kilograms, 98 percent of the same 98.98 kg. This does not match the task.

Relation to reality

According to the USDA National Nutrient Database contain raw potatoes with Flesh and Skin approximately 79.34 percent water. The puzzle is also formulated with watermelons, after all, have 91.45 percent water. Winter melons even have 96.10 percent, cucumber, unpeeled and peeled 95.23 96.73 percent.