коротко напишу : почему в вопросе " СКОЛЬКО ТЫ ВЕСИШЬ?" надо правильно начинать именно " How much do you weigh ? а не "how many....." я же спрашиваю конкретную цифру (исчисляемую).
Потому что вес - неисчисляемое существительное. Именно оно подразумевается в данном предложении, которое значит примерно "Насколько большой твой вес"?
С many будет:
How many kilos do you weight?
The tricky part is that when you say "How much do you weigh?", you could be talking about weight or you could be talking about pounds. Similarly, with money, you could ask "How much money do you have?", you could be talking about money or dollars.
How much (weight) do you weigh? (we would never actually use "weight" in this sentence)
How many (pounds) do you weight? (we would always use the word "pounds" in this sentence)
So technically, they are both correct. However, in real life, we always ask the former.
How much (money) do you have?
How many (dollars) do you have?
Both of those are correct and used regularly when discussing money.