Answer: -3,7
Step-by-step explanation:
Answer:
Explanation:
You can build a two-way relative frequency table to represent the data:
These are the columns and rows:
Car No car Total
Boys
Girl
Total
Fill the table
- <em>30% of the children at the school are boys</em>
Car No car Total
Boys 30%
Girl
Total
- <em>60% of the boys at the school arrive by car</em>
That is 60% of 30% = 0.6 × 30% = 18%
Car No car Total
Boys 18% 30%
Girls
Total
By difference you can fill the cell of Boy and No car: 30% - 18% = 12%
Car No car Total
Boy 18% 12% 30%
Girl
Total
Also, you know that the grand total is 100%
Car No car Total
Boy 18% 12% 30%
Girl
Total 100%
By difference you fill the total of Girls: 100% - 30% = 70%
Car No car Total
Boy 18% 12% 30%
Girl 70%
Total 100%
- <em>80% of the girls at the school arrive by car</em>
That is 80% of 70% = 0.8 × 70% = 56%
Car No car Total
Boy 18% 12% 30%
Girl 56% 70%
Total 100%
Now you can finish filling in the whole table calculating the differences:
Car No car Total
Boy 18% 12% 30%
Girl 56% 14% 70%
Total 74% 26% 100%
Having the table completed you can find any relevant probability.
The probability that a child chosen at random from the school arrives by car is the total of the column Car: 74%.
That is because that column represents the percent of boys and girls that that arrive by car: 18% of the boys, 56% of the girls, and 74% of all the the children.
We would have to see the square to determine that
The answer is 6*square rooted*2
Answer:
<u>The number of pens = 120 and the number of pencils = 200</u>
Step-by-step explanation:
Let the number of pens x, and the number of pencils is y
the cost of one pen $1, and the cost of one pencil $0.5
The cost of the whole purchase was $220
1 * x + 0.5 * y = 220
x + 0.5 y = 220 ⇒ eq.(1)
there were 80 more pencils than pens
y - x = 80 ⇒ eq.(2)
from eq.(2) x = y - 80
By substitution with x from the last equation at eq.(1)
∴ (y - 80) + 0.5 y = 220
1.5y = 220 + 80 = 300
y = 300/1.5 = 200
x = y - 80 = 200 - 80 = 120
<u>So, the number of pens = 120 and the number of pencils = 200</u>
