70℅ = 14
100 = X
70X = 1400
X = 1400/70
X = 20
20 Euros is the full price
The way it is written, none of them.

The "a"s cancel out.
Answer:
and 
Step-by-step explanation:
If two equations are given, we can solve one of the equation in terms of single variable and put it in the other equation which will further give the value of x and y.
For the given equations:
Equation:1
Equation:2
Solving equation multiply equation 2 with 4 on both the sides
Equation 3
Subtracting Equation:3 from Equation:1

Putting value of 'y' in Equation:2 which will give the value of x

Using the law of cosines:
The grocery store to the school:
Distance = √(7^2 + 10^2 - 2*7*10*cos(100)
Distance = 13.16 miles
The movie store to the school:
Distance = √(7^2 + 10^2 - 2*7*10*cos(120)
Distance = 14.80 miles
The friend is further away.