90-n=3n
90=4n
22.5=n
Final answer 22.5
Let`s assume that points M, N and P are the touching points of those 3 circles:Then:Y M + M Z = 14,Z N + N X = 20X P + P Y = 18And also: M Z = ZN, Y M = P Y and N X = X P.Now we have a system of 3 equations ( Y M, M Z and X P are the radii of each circle ):Y M + M Z = 14M Z + X P = 20X P + Y M = 18 Y M - M Z = - 14+X P + Y M = 18 X P - M Z = 4Y M - M Z = - 14+M Z + X P = 20 X P - Y M = 6 /* ( - 1 )X P - M Z = 4 X P + Y M = - 6 X P - M Z = 4 Y M - M Z = - 2 Y M + M Z = 14 2 Y M = 12 => Y M = 6M Z - 6 = 2 => M Z = 8X P + 6 = 18
X P = 12
Radii of the circles are: 12, 8 and 6.
12. Make equation and plug in
13. Proportion
14. Finding a constant rate, and then manipulate
12. Where x is miles driven, and y is answer, and z is days
19.95z+0.15x=y
Plug in two values
19.95 x 2 + 0.15 x 250 = y
39.93+37.5 = y
y=77.43
13. 5:2 as 175:x
5/2 = 175/x
x = 70
70+175=245
14. 260:5 = x:1
260/5=x/1
x = 52
52:1 = y:9
52/1 = y/9
y = 468
I hope you understand the process.
It should be B because it’s going down 4
( 1635 ÷ 24 ) • 100 = monthly income
1635 ÷ 24 = 68.125
68.125 • 100 = $6812.50 a month
