Because if X is ten then the equation is complete
A = P + SI
A-P = SI
5425-5000 = 425
THEREFORE THE SIMPLE INTRESTE IS $425
SI = PTR/100
425 = 5000×1×R/100
425×100/5000×1=R
425×100÷5,000×1 = 8.5%
THEREFORE THE RATE IS 8.5%
Solve using equations:
Gina 11 = a+b+c
Sam 27 = 2a+3b+2c
Robby 19= a+2b+2c
Gina *2 give 22=2a+2b+2c (subtract this from Sam to give)
b=5
the subtract Robby from Gina *2 to give a=3
[Question 1]
let d = number of dramas Gina rented, c = # of comedies, and t = # of documentaries:
[equation a] d + c + t = 11
[equation b] 2d + 3c + 2t = 27
[equation c] d + 2c + 2t = 19
if we subtract [a] from [c] we get:
[equation d] c + t = 8
if we subtract [c]*2 from [b] we get:
[equation e] -c - 2t = -11 or
[equation e] c + 2t = 11
Now we can subtract [e] from [d] to solve for t:
t = 3
Now put in 3 for t in [d] or [e] to solve for c:
c + 2(3) = 11
c + 6 = 11
c = 5
So she rented 5 comedies and 3 documentaries which leaves 3 dramas (which is answer A)
