Question 1173954
let x = the original length of the traffic jam.
x + .25 * x = 1.25 * x = 4
solve for x to get x = 4 / 1.25 = 3.2.
that's the length of the traffic jam before the period of time that it increased.
the increase was 4 - 3.2 = .8
that's your answer.
.25 * 3.2. = .8 + 3.2 = 4
solution is confirmed to be good.
solution is .8 kilometers increase in the period of time.