X= 5
multipules of 5
thinking of the factors of 5
All outcomes of three children (using G for girl and B for boy)
GGG, GGB,GBG,GBB,BGG,BGB,BBG,BBB
1) exactly two is 3 out of 8 total outcomes, or 3/8
2) all sons is one outcome, or 1/8
Answer:
i)The correct option is D.) 99.74%
ii) The correct option is B.) 68.26%
Step-by-step explanation:
i) P(10≤X≤70) = P( (10−40)/10 ≤Z≤ (70−40
)/10 ) = Pr(−3≤Z≤3)
= 0.9987 - 0.0013 = 0.99734
Therefore the percentage of Jen's monthly phone bills are between $40 and $100 is D.) 99.74%
ii)P(2.1≤X≤3.1) = P( (2.1 − 2.6) /0.5 ≤ Z ≤ (3.1−2.6
)/0.5) = Pr(−1 ≤Z ≤1)
)
= 0.8413 − 0.1587 = 0.6826
Therefore the percentage of students at college have a GPA between 2.1 a,d 3.1 is B.) 68.26%
To factor quadratic equations of the form ax^2+bx+c=y, you must find two values, j and k, which satisfy two conditions.
jk=ac and j+k=b
The you replace the single linear term bx with jx and kx. Finally then you factor the first pair of terms and the second pair of terms. In this problem...
2k^2-5k-18=0
2k^2+4k-9k-18=0
2k(k+2)-9(k+2)=0
(2k-9)(k+2)=0
so k=-2 and 9/2
k=(-2, 4.5)