SOLUTION: Ann has walked 8 km with a velocity of 4 km/h. Now she will jog for some time with a velocity of 8 km/h. How long does she have to jog in order to have an overall average velocity

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Question 1070375: Ann has walked 8 km with a velocity of 4 km/h. Now she will jog for some time with a velocity of
8 km/h. How long does she have to jog in order to have an overall average velocity of 5 km/h?
(A) 15 min (B) 20 min (C) 30 min (D) 35 min (E) 40 min
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
            
            SPEED     TIME      DISTANCE

WALK         4        8%2F4=2       8

JOG          8         t         8t

Totals              t+2        8t+8


Question asks for overall speed to be 5 kilometer per hour.
%288t%2B8%29%2F%28t%2B2%29=5

8t%2B8=5t%2B10
3t=2
3t%2F3=2%2F3
highlight%28t=2%2F3%29, forty minutes.



-----------removed incorrect steps and results-----------

Answer by MathTherapy(10551) About Me  (Show Source):
You can put this solution on YOUR website!

Ann has walked 8 km with a velocity of 4 km/h. Now she will jog for some time with a velocity of
8 km/h. How long does she have to jog in order to have an overall average velocity of 5 km/h?
(A) 15 min (B) 20 min (C) 30 min (D) 35 min (E) 40 min
Correct answer: 

IGNORE all other NONSENSICAL answers!