I would use elimination
2x+3y = 7
2x-y = -5
Subtract those equations
4y = 12
Y = 3
Now plug in 3 for any y value
2x - 3 = -5
2x = -2
X = -1, y = 3
Answer:
21 yards
Step-by-step explanation:
12 + 8 = 20
2/3 + 1/3 = 1
20 + 1 = 21 yards of gold ribbon
Volume of the sphere = 3/4 pi r^3
The spheres radius is one third of the hemisphere's so radius of hemisphere = 3r
Volume of the hemisphere = 1/2 * 4/3 pi (3r)^3
= 2/3 * 27 pi r^3
= 18 pi r^3
So vol hemisphere / vol sphere = 18 pi r^3 / 4/3 pi r^3 = 18 * 3/4 = 13.5
Hemisphere is 13.5 times the volume of the sphere.
25,000 - 8,500 = 16,500
16,500 :1250 = 13 years and 2 months
