Answer:
8%
Step-by-step explanation:
Interest = $112
Principal = $1400
Rate = Percentage Per Year
Time = 1 Year
I = PRT
![112 = (1400 )(R)(1)](https://tex.z-dn.net/?f=112%20%3D%20%281400%20%29%28R%29%281%29)
Multiply everything together...
![\frac{112}{1400} = \frac{1400R}{1400}](https://tex.z-dn.net/?f=%5Cfrac%7B112%7D%7B1400%7D%20%3D%20%5Cfrac%7B1400R%7D%7B1400%7D)
Divide both sides by 1400.
![\frac{112}{1400} = R](https://tex.z-dn.net/?f=%5Cfrac%7B112%7D%7B1400%7D%20%3D%20R)
Simplify.
![\frac{112}{1400} = \frac{2}{25}](https://tex.z-dn.net/?f=%5Cfrac%7B112%7D%7B1400%7D%20%3D%20%5Cfrac%7B2%7D%7B25%7D)
![\frac{2}{25} = 0.08](https://tex.z-dn.net/?f=%5Cfrac%7B2%7D%7B25%7D%20%3D%200.08)
Simplify the fraction. Feel free to flip the equation (Put the R on the right side of the = instead of the left).
![\frac{2}{25} = 0.08](https://tex.z-dn.net/?f=%5Cfrac%7B2%7D%7B25%7D%20%3D%200.08)
Change the fraction into a decimal.
![R = 0.08](https://tex.z-dn.net/?f=R%20%3D%200.08)
Turn this number into a percentage and we have our answer:
R = 8% per year
<span>0.3278
Use combination formula ((20C4)*(15C3))/(35C7) = 0.3278
20C4 - combinations of 4 females from 20
15C3 - combinations of 3 males from 15
35C7 - all possible combinations of 7 students from 35 students in total</span>
<span>150 x 1.2 x 1.2 = 216 are females</span>
It is 3f - 9
So you multiply f by 3 and subtract 9
As simple as that!