Which ordered pair (a, b) is a solution to the given system of linear equations?
2 answers:
Answer:
Option C
Step-by-step explanation:
Given is a systems of equations in two variables a and b.
3a+b=10
-4a-2b=2
Let us solve this and find solution.
We can do this by elimination method
I equation x 2 gives
Add these two equations to get
2a = 22
Divide by 2
We get a=11
Substitute in I equation
3(11)+B=10
b =10-33 =-23
Hence solution set is
(11,-23)
Option C is the right anser.
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Answer: 15/91 which is choice B
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There are two methods to find this answer.
Method 1) We have 6 girls and 8+6 = 14 students. The probability of picking a girl is 6/14 = 3/7. After the first girl is chosen, we have 5 girls left out of 14-1 = 13 students overall. The probability of picking another girl (assuming the first selection was a girl) is 5/13. Multiply these probabilities: (3/7)*(5/13) = (3*5)/(7*13) = 15/91
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Method 2) We can use the nCr combination formula. Order does not matter.
We have nCr = 6 C 2 = 15 ways to pick 2 girls. See the attached image below for the steps (figure 1)
Out of nCr = 14 C 2 = 91 ways to pick 2 students. See the attached image below for the steps (figure 2)
So that's another way to get the answer 15/91.
