In an examination 31 candidate passed Chemistry,29 passed Physics 3 failed both subjects.lf 50 candidates sat for the examination how many of them passed Chemistry only.
Let x be the number who passed both.
x + 31-x + 29-x + 3 = 50
-x = -13
x = 13
number who passed Chemistry only = 31-x
= 31-13 = 18
Correct
Using Venn diagram to solve it
sorry guys textbook answers might be wrong at times
Yes
Pls explain i dont understand and the answer differs from that at the back of tge textbook
So how do you solve it using the venn diagram
Some authors are very good on making mistakes at the back of the textbooks.
To solve the problem using a Venn diagram, we first draw two circles intersecting each other lightly. Let's label them as 'C' (for Chemistry) and 'P' (for Physics).
We are given that 31 students passed Chemistry, and 29 passed Physics. We write the numbers 31 and 29 in the corresponding regions of the circles.
Next, we are told that 3 students failed both subjects. We write this number in the intersection of the circles.
Now, using the information we have, we can find the number of students who passed both subjects. This is the number that goes in the intersection of the circles. To do this, we subtract the number of students who failed both subjects from the total number of students:
50 - 3 = 47
So, 47 students passed at least one of the subjects. Since 31 passed Chemistry and some of those may have also passed Physics, we know that at most 31 students passed only Chemistry. We write this number outside the circle labelled 'C'.
We can fill in the remaining numbers in the diagram by subtracting the numbers we have already placed from the total number of students:
* The number of students who passed only Physics: 29 - (47 - 31) = 13
* The number of students who passed both Chemistry and Physics: 47 - 13 - 18 = 16
So, according to the Venn diagram, 18 students passed Chemistry only.