The answer is the first one
Use the pythagorean theorem a.k.a

c is the hypotenuse while a & b are the legs


subtract 225 from 289

square root both b and 64
the other leg is equal to 8
35/7 (total $ divided by total units)= 5
1 unit = $5
Sitis units times 5
4 • 5 = $20
Sitis has $20
I'm assuming it's 10^6, so 10 would be the base, and 6 would be the exponent.
Remark
You are using the midpoint formula. Instead of finding the midpoint, you are looking for one of the points, so you have to rearrange the formula a little bit.
Givens
Midpoint (4,2)
One endpoint (6,1)
Object
Find the other endpoint.
Formula
m(x,y) = (x1 + x2)/2, (y1 + y2)/2)
Solution
Find the x value
4 = (6 + x2)/2 Multiply both sides by 2
4*2 = 6 + x2 Subtract 6 from both sides.
8 - 6 = x2
x2 = 2
Find the y value
2 = (1 + y2)/2 Multiply by 2
4 = 1 + y2 Subtract 1 from both sides.
4 - 1 = y2
y2 = 3
Conclusion
R(x,y) = (2,3)