Question

All 35 students in math class are taking at least one science course of Physics,
Chemistry or Biology.
16 take Physics
18 take Biology
21 take Chemistry
7 take Physics and Chemistry but not Biology
s take Biology and Chemistry but not Physics
2 take Physios and Biology but not Chemistry
Then the number of students only taking one science course is.​

Answer 1

Answer:

*I want to know that you have written s instead of numeric value so is it wrong or is it in the question. Kindly check, the method will be same.

16 students take physics and out of which 7 take Physics and Chemistry and 2 take Physios and Biology. So, 16-2-7=16-9=7. Thus 7 students take only physics. Then, 18 take biology and out of which s take Biology and Chemistry and 2 take Physics and Biology. So, 18-2-s=16-s. Thus 16-s students don't take only biology. By the same method we can find for chemistry and we will get, that 14-s students have only taken chemistry. Now we have to add it and we get 7+14-s+16-s=37-2s. Then, subtract 7+2+s from 35 and we will get the sum of students who have taken only one science course in an equation form. So, 35-(9+s)=26-s.

Now, 37-2s=26-s

         37-2s+s=26

         37-s=26      

        -s=26-37=-11

         Thus, s=11, now put the value and we will get 37-22=15, which means          16 students have only taken one course.

I hope it helps. If i have done something wrong then please correct it, i hope you have understood the concept well.

Step-by-step explanation: