Velocity is vector quantity but speed is scalor quantity . why ?

speed speed scalar quantity is the rate of at which an object covers distance on the other hand velocity is a vector quantity it is direction aware.velocity is the rate at which the position changes.the average velocity is the displacement or position change Per time ratio.so velocity is a vector quantity but speed is a scalar quantity

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles