Answer:
4 students
Step-by-step explanation:
The total number of students is given by:
Where N is the total number of students, A is the number of students that have taken Math 2A, B is the number of students that have taken Math 2B, and C is the number of students that have taken Math 2C:
4 students in Group A have taken all three classes.
*The number of students that have taken two classes has be subtracted so those students do not get counted twice
First, we need to convert all the fractions to have the same denominator. 10 and 25 are both multiples of 100, so 100 would be appropriate.
Sam has a 7/25 chance. Because we want ?/100, something needs to change. To get from 25 to 100, you need to times 25 by 4, right? So, do the same with the 7.
7 x 4 = 28. Therefore Sam has a 28/100 chance.
Sue has 3/10. Using the same method, we can see that 3 needs to be multiplied by 10 (because 10 times 10 = 100). So Sue has a 30/100 chance.
Tom is already in the fraction we like, so just keep this as 21/100.
Now, add 28/100, 30/100 and 21/100 to get 79/100.
Because won of them will get the role of class president, we know that the probability adds to 1. To get a full probability (100/100, or 1), what needs to be added to 79/100?
Another way of going about this is 100/100-79/100. The answer is 21/100
The probability of Liz winning is 21/100.
Let me know if this is still unclear, I would be more than happy to explain in more detail if necessary :)
Answer: 2,680 bulbs were used in all.
I added all of them up so 1240 + 1350 + 90 which equals 2,680.
If you have any questions let me know, have a great day!
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