Two different age groups were surveyed about the amount of time they spent on social media.
The results are shown in the two frequency
polygons below. The same time intervals were
used for both graphs.
11-year old students
15-year old students
80
80
70
70-
60
60-
50
a) How many 15-year old
students took part in
the survey?
(1)
b) How many more 15-year
old students than 11-year
old students spent
between 35 and 45 mins
on social media?
50
Frequency
Frequency
30-
30
20
20-
10
10
0
0
0 10 20 30 40 50 60 70 80
Time (mins)
10 20 30 40 50 60 70 80
Time (mins)
(1)
Total marks: 2​

answer: c, the green line

step-by-step explanation:

there is no black line, eliminate b.

simple interest implies periodic payments, but the red line shows no payments, eliminate d.

simple interest has equal payments. if paid say every day, the graph is about a straight line (actually a stairstep).

the yellow line is not straight, eliminate a.

check: the green line is straight, answer is c.

simple interest with positive interest rate gives a straight line sloping up to the right. green line:

g(t) = $100 + ($200-$100) ÷ (20 years) × (t years)

= $100 + (4%/year) × ($100)(t years)

incidentally, the yellow line curving upward represents continuously compounded interest

y = $100 × 2^(t years / (14 assuming the yellow line hits $200 at 14 years. 2^0 is 1, so y(0) = $100; 2^(14/14) is 2, so y(14) = $200.

the correct answer option is (2x-3)(2x+3).

step-by-step explanation:

we are given the following expression and we are to factorize it:

we are to find such factors that when multiplied they give a result of 36 (9 x 4 = 36) and when added they give a result of 0.

the two such factors of 36 are negative six and postive six.

factorizing the given expression to get:

therefore, the correct factorization of is (2x-3)(2x+3).