15=-2(2t-1) -- expand brackets
15=-4t+2 -- subtract 2
13=-4t -- switch signs, best to have a positive variable
4t=-13
t=-13/4
7.2 would be bigger than 7.09
Answer:
Step-by-step explanation:
<em>Refer to attached</em>
- Height of plants (h) >> Frequency >> Midpoint >> Frequency x midpoint
- 0 <h < 10 >> 1 >> 5 >> 5
- 10 <h < 20 >> 4 >> 15 >> 60
- 20 <h < 30 >> 7 >> 25 >> 175
- 30 <h < 40 >> 2 >> 35 >> 70
- 40 <h < 50 >> 3 >> 45 >> 135
- 50 <h < 60 >> 3 >> 55 >> 165
Sum of frequencies = 20
Sum of frequency x midpoint product = 610
<u>Mean height </u>
I think the answer would be
X=1.5
Y= -10 or -12 or 12
Sorry I'm not sure
The answer to the question is C.