The question below is a simple calculation in the textbook of elementary school students, but not all adults can find the correct answer in a short time. Many people even have to shake their heads in frustration because they cannot find a number that satisfies the conditions of the calculation given in the question.

The problem gives 3 cups of water (blue, yellow, black) with the given data that 3 blue cups added together = 42; blue cup + 2 yellow cups = 24; yellow cup + black cup + blue cup = 26. The question is how much is blue cup + black cup - yellow cup?

Please observe carefully to give the correct answer. My advice is to take a pen and paper and calculate carefully to avoid confusion.

If you find the answer, quickly register yourself in the top smartest people by leaving the answer in the comment box below.

Khanh Son