Answer:
a) 320 students
b) 25 students
Step-by-step explanation:
Number of 18-years old in the survey:
(We add all frequency points for each line)
0 + 30 + 20 + 60 + 70 + 40 + 60 + 40 + 0 = 320 students
Number of 18 year old spending between 25 and 35 minutes: 40 + 65 = 105
Number of 12 year old spending between 25 and 35 minutes: 30 + 50 = 80
105 - 80 = 25 students
30-(11+(18-(48/8×2))+7)+15
= 30-(11+(18-12)+7)+15
= 30-(11+6+7)+15
= 30-24+15
= 21
Answer:
Equation of a line, y = mx+c
Slope (m)= (Y2-Y1)/(X2-X1), let Y2=7, Y1=3 , X2=2 and X1=1
m=(7-3)/(2-1)
= 4/1
= 4
Picking any value of y and its corresponding x including m, put them into the equation of the line
y=mx+c
3 =4(1)+c
3=4+c
3-4=c
-1=c
y=mx+c
y=4x+(-1)
y=4x-1
We know that
We can write an Arithmetic Sequence as a rule:
<span>an = a1 + d(n−1)</span>
where
<span>a1 = the first term
<span>d =the "common difference" between terms
in this problem
a1=15 a2=7 a3=-1 a4=-9 ..... an=-225
d=a2-a1
d=7-15-----> d=-8
</span></span>an = a1 + d(n−1)
for
an=-225
d=-8
a1=15
find n
-225=15+(-8)*(n-1)--> (n-1)=[-225-15]/-8----> n-1=30---> n=30+1---> n=31
the answer is31
