Answer:
7/40
Step-by-step explanation:
There are 3 girls+9 boys = 12 students in the 7th grade
P (girl in 7th grade) = girls/ total
= 3/12 = 1/4
There are 7 girls+3 boys = 10 students in the 8th grade
P (girl in 8th grade) = girls/ total
= 7/10
P(7th grade girl, 8th grade girl) = 1/4 * 7/10 = 7/40
Let Lin be x years old.
Lin = x
Frank = 4x
<span>The difference in their ages is equal to Lin’s age plus 8
</span>⇒4x - x= x + 8
Solve x:
4x - x= x + 8
Combine like terms:
3x = x + 8
Take away x from both sides:
2x = 8
Divide by 2 on both sides:
x = 4
Lin is 4 years old.
Frank is 4 x 4 = 16 years old.
Answer: Lin is 4 years old and Frank is 16 years old.
3x+9=6x
-9 -9
—————
3x=6x-9
-6x -6x
—————
3x-6x=-9
-3x=-9
x=3
hope it helped
The mean of 10 randomly selected students is definitely more likely to be closer to 75. 10 randomly selected students to include information and are more like to reflect the class’s scores. Consider an extreme example. Seventy-five students in a class of 100 earned perfect scores. The other 25 earned zeros. The average score of the class would be 75. A sample of 10 random students would almost certainly include more 100s then 0s, but both would be included in the sample. The mean of this samples score is closer to 75 than any individuals.
