Let's first define variables.
y: number of shares of $ 10
x: number of shares of $ 12
We write the system of equations:
10x + 12y = 210
y = 2x + 5
Solving the system:
x = 75/17
y = 235/17
Answer:
she has:
75/17 shares of $ 12
235/17 shares of $ 10
We're going to solve each of the systems to determine the solution.
<u>System
</u>

using a graph tool
the solution is the line 
see the attached figure N 
<u>System
</u>

using a graph tool
the solution is the shaded area
see the attached figure N 
<u>System
</u>

using a graph tool
The system has no solution
see the attached figure N 
<u>System
</u>

using a graph tool
the solution is the shaded area
see the attached figure N 
therefore
<u>the answer is</u>
<u>System
</u>

Answer:
a) distance covered by hare d1 = 8t
b) distance covered by tortoise d2 = 5t + 550
c) ∆d = 550 - 3t
Step-by-step explanation:
Given;
Speed of hare u = 8m/s
Speed of tortoise v = 5 m/s
Initial distance of tortoise d0 = 550 m
a) using the equation of motion;
distance covered = speed × time + initial distance
d = vt + d0
For hare;
d0 = 0
Substituting the values;
d1 = 8t + 0
d1 = 8t
b)using the equation of motion;
distance covered = speed × time + initial distance
d2 = vt + d0
For tortoise;
d0 = 550m
Substituting the values;
d2 = 5t + 550
d2 = 5t + 550 m
c) the number of meters the tortoise is ahead of the hare.
∆d = distance covered by tortoise - distance covered by hare
∆d = d2 - d1
Substituting the values;
∆d = (5t + 550) - 8t
∆d = 550 - 3t
It'd be A since dividing on a negative coefficient results flipping the sign of the inequality and results in a different impact