Answer:
605 boys
Step-by-step explanation:
If the ratio of boys to girls is 5:7
and there are 847 girls
we can plug this value into the ratio by doing something like:
5:7
= 5/7
= x/847
Because the ratio has to be the same, we can substitute x for the number of boys and solve by the cross method or whatever you guys call it.
5 x
--- x ------
7 847
The x in the middle is just to show the direction you are multiplying.
the 5 is multiplied by the 847 and the 7 is multiplied by x.
847 * 5 = 4,235
4,235 divided by 7 is 605
605 is your answer.
The cross method can be used in most situations.
* is used to represent multiplication btw
12(3w+8)=25
36w+96=25 ( I used the distributive property)
-96 . -96
36w=-71
w=-1.972222.... ( I divided both sides by 36)
Answer:
Step-by-step explanation:
Given
Required
The locus of P
Express as fraction
Cross multiply
Calculate AP and BP using the following distance formula:
So, we have:
Take square of both sides
![4 * [(x +1)^2 + (y +2)^2] = (x - 2)^2 + (y - 4)^2](https://tex.z-dn.net/?f=4%20%2A%20%5B%28x%20%2B1%29%5E2%20%2B%20%28y%20%2B2%29%5E2%5D%20%3D%20%28x%20-%202%29%5E2%20%2B%20%28y%20-%204%29%5E2)
Evaluate all squares
![4 * [x^2 + 2x + 1 + y^2 +4y + 4] = x^2 - 4x + 4 + y^2 - 8y + 16](https://tex.z-dn.net/?f=4%20%2A%20%5Bx%5E2%20%2B%202x%20%2B%201%20%2B%20y%5E2%20%2B4y%20%2B%204%5D%20%3D%20x%5E2%20-%204x%20%2B%204%20%2B%20y%5E2%20-%208y%20%2B%2016)
Collect and evaluate like terms
![4 * [x^2 + 2x + y^2 +4y + 5] = x^2 - 4x + y^2 - 8y + 20](https://tex.z-dn.net/?f=4%20%2A%20%5Bx%5E2%20%2B%202x%20%2B%20y%5E2%20%2B4y%20%2B%205%5D%20%3D%20x%5E2%20-%204x%20%2B%20y%5E2%20-%208y%20%2B%2020)
Open brackets
Collect like terms
Divide through by 3
Answer:
6
Step-by-step explanation:
Call pentagon p, circle c and triangle t
We have 2c + 2p = 2p + 2t + c
p = 5, t = 3 so
2c + 2(5) = 2(5) + 2(3) + c
2c + 10 = 10 + 6 + c
2c = 6 + c
c = 6
