Answer:
x=# of boys
x+7=# of girls
x+x+7=25
2x+7=25
2x=25-7
2x=18
x=18/2
x=9 boys
x+7=16 girls
If you don't understand variables use trial and error.
Boys Girls
1 8
2 9
3 10
4 11
5 12
6 13
7 14
8 15
9 16 9+16=25 students
You could start this way...
Boys Girls
12 13
11 14
10 15
9 16 16 is 7 more than 9
Answer: he invested $46062.5 at 6% and $23031.25 at 10%
Step-by-step explanation:
Let x represent the amount which he invested in the account paying 6% interest.
Let y represent the amount which he invested in the account paying 10% interest.
He puts twice as much in the lower-yielding account because it is less risky.. This means that
x = 2y
The formula for determining simple interest is expressed as
I = PRT/100
Considering the account paying 6% interest,
P = $x
T = 1 year
R = 6℅
I = (x × 6 × 1)/100 = 0.06x
Considering the account paying 10% interest,
P = $y
T = 1 year
R = 10℅
I = (y × 10 × 1)/100 = 0.1y
His annual interest is $7370dollars. it means that
0.06x + 0.2y = 7370 - - - - - - - - - -1
Substituting x = 2y into equation 1, it becomes
0.06 × 2y + 0.2y = 7370
0.12y + 0.2y = 7370
0.32y = 7370
y = 7370/0.32
y = $23031.25
x = 2 × 23031.25
x = 46062.5
Answer: 
Step-by-step explanation:
1. If you join the top part and the bottom part of the figure, you obtain a sphere. Then, you must apply the formula for calculate the surface area of a sphere:

Where r is the radius (
)
2. Then:

3. The formula for calculate the suface area of the red part, which is a cylinder, is:

Where h is the height (h=32mm)
4. Then:

5. So, the total surface area is:

Answer:
your answer is -2
Step-by-step explanation:
Hope helps
:3