Two different age groups were surveyed about the amount of time they spent on social media.
The results are shown on the two frequency
polygons below. The same time intervals were
used for both graphs.
a) How many 18-year old
students took part in
the survey?
12-year old students
18-year old students
+
80+
70
60
50
940
30
20
801
70
60
50
740
Frequency
L 30
b) How many more 18-year
old students than 12-year
old students spent
between 25 and 35 mins
on social media?
20
10
10
0
0 10 20 30 40 50 60 70 80
Time (mins)
0
0 10 20 30 40 50 60 70 80
Time (mins)

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional

answer: h=5.6 i don't really know how to put into words, so i though i would let you do that. i hope i was able to some

step-by-step explanation:

18 = 6(h)+1/2

18 = 6h+1/2

18-1 = 6h/2

17 = 3h

17/3 = h

h = 5.6