A class of 47 students took examination in algebra and geometry. If 29 passed algebra and 26 passed geometry and 4 failed in both subjects, how many passed both subjects?

With solution please, tnx...

47-29=18 failed algebra

47-26=21 failed geometry
4 failed both

18+21-4=35 failed something
so, 47-35=12 passed both

NO ANSWER

12

To find out how many students passed both subjects, we can use the principle of inclusion-exclusion.

Let's break down the information given:
- 29 students passed algebra
- 26 students passed geometry
- 4 students failed in both subjects

To find the number of students who passed both subjects, we can subtract the students who failed in both subjects from the total number of students who passed.

Step-by-step solution:
1. Find the total number of students who passed at least one subject:
- Total students who passed either algebra or geometry = students who passed algebra + students who passed geometry = 29 + 26 = 55

2. Subtract the number of students who failed in both subjects from the total number of students who passed at least one subject:
- Students who passed at least one subject - students who failed in both subjects = 55 - 4 = 51

Therefore, 51 students passed at least one subject.

3. To find the number of students who passed both subjects, subtract the number of students who passed at least one subject from the total number of students:
- Total number of students - students who passed at least one subject = 47 - 51 = -4

Since it's not possible for there to be a negative number of students, it means that something went wrong in the calculations.

However, based on the given information, it seems contradictory to have 51 students who passed at least one subject when the total class size is 47. Therefore, there may be an error or missing information in the question itself.

Please double-check the information provided or rephrase the question if necessary.