First get the tangent vectors by differentiating r1 and r2

Evaluate at t=0

Use identity for angle between 2 vectors:

Evaluate dot product and unit vectors:

Sub into identity and solve for theta:

Answer:
Angle of intersection is about 79 degrees.
64 divided by 8 is 8. 8 pints fit in one gallon. She carries 2 gallon jugs, so that's 16 pints. So each day she carries 4 2 gallon jugs to meet her catering business demands.
Answer:
All real numbers.
Step-by-step explanation:
25-4x=15-3x+10-x
25-4x-(-3x)-(-x)=15+10
25-4x+3x+x=25
25-x+x=25
25=25