Answer:
The mean = 17.54
Step-by-step explanation:
Form a table as below;
<u>Interval Frequency{f} Midpoint of frequency{x} fx </u>
1-7 19 4 76
8-10 14 9 126
11-15 15 13 195
16-20 20 18 360
21-35 10 28 280
36-50 13 43 559
Sum 91 1596
The mean of grouped data = Sum of { Interval Midpoint * Frequency } /Sum of frequency
The mean= 1596 / 91
The mean = 17.54
Answer: There were 525 pine trees.
Step-by-step explanation:
Given: Total trees = 1250
Percentage of oak trees = 32%
Percentage of birch trees = 26%
Since remaining trees are pine trees.
Percentage of pine trees = 100% - 32% - 26%
=42%
The number of pine trees = 42% of 1250
= 0.42 ×1250
= 525
Hence, there were 525 pine trees.
Answer:

Step-by-step explanation:
the third option
Let us assume the number to be = x
Then
(80/100) * x = 56
4x/5 = 56
4x = 56 * 5
4x = 280
x = 280/4
= 70
The value of the unknown number is 70. I hope the procedure is clear enough for you to understand. You can always use this method for solving similar problems in future without requiring any help from outside. Only thing that needs to be taken care of is the calculation part.