4+3p≥40
He needs to have 40 or more to get to the finals so 4+3p has to be 40 or more
X = pencils, y = pens
8x + 6y = 8.50
4x + 4y = 5.....multiply by -2
----------------
8x + 6y = 8.50
-8x - 8y = -10 (result of multiplying by -2)
-----------------add
-2y = - 1.50
y = -1.50 / -2
y = 0.75 <=== pens cost 0.75
4x + 4y = 5
4x + 4(0.75) = 5
4x + 3 = 5
4x = 5 - 3
4x = 2
x = 2/4
x = 0.50 <== pencils cost 0.50
Answer:
60 students
Step-by-step explanation:
The confidence interval of a proportion is given by:

Where 'p' is the proportion of students who responded 'yes', 'z' is the z-score for a 95% confidence interval (which is known to be 1.960), and 'n' is the number of students in the sample.
If the confidence interval is from 0.584 to 0.816, then:

60 students were in the sample.
Do the following:
$8.40-$7.15=$1.25
Then divide 1.25 by the difference of tickets which is 3
1.25/3=0.42 (that's rounded to nearest cent)
Answer:
30:16-15:8 That is simplified and I divided it by two.