The final price is the cost plus the tax.
Since we know the tax and a percent, we can write this as
T = C(1+r)
T = what Graham paid = $87.45
C = cost before tax
r = tax rate expressed as a decimal = .40
Plugging in what we know
87.45 = C (1+.4)
87.45 = C(1.4)
Divide both sides by 1.4
C = $62.46
Find delta y/delta x
(10-7)/(15-12)=3/3=1, (15-10)/(20-15)=5/5=1
y=x+b, using any point, I'll use (20,15) we can solve for b...
15=20+b
b=-5 so our line is:
y=x-5, and we want to know when y=17
17=x-5
x=22
so n=22
Set up the ratios and cross multiply.
24/18=x/6
8=x
X should be around 1.5625, assuming that -4 is squared is not in a parenthesis. So, the problem should be -20=-4^2(sqrtx). Divide -20 by -16 to get 1.25. Then square 1.25 and sqrt x to get 1.5625.
Answer:
7 minutes
Step-by-step explanation:
1 kilometer / 7.2 minutes
x kilometers/ 50.4 minutes
cross-multiply
x*7.2 = 1*50.4
divide by 7.2 both sides
x= 50.4/7.2= 7 minutes