SOLUTION: A boy covered 28km in 5 hours. He cycled part of the way at 11km/h and walked the rest of the way at 5km/h. How far did he walk?

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Question 1072531: A boy covered 28km in 5 hours. He cycled part of the way at 11km/h and walked the rest of the way at 5km/h. How far did he walk?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
RT=D, basic travel rate rule 

                 SPEED       TIME          DISTANCE
CYCLED            11         %2828-d%29%2F11     28-d
WALKED             5         d%2F5            d
Totals                        5             28


d, the unknown distance walked.
highlight_green%28%2828-d%29%2F11%2Bd%2F5=5%29

Answer by ikleyn(52797) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let W be the distance (in kilometers) he walked.


Then the distance he cycled is (28-D) kilometers.


The time walking is W%2F5 hours.
The time he cycled is %2828-W%29%2F11.


Your equation is

W%2F5+%2B+%2828-W%29%2F11 = 5.


To solve it, multiply both sides by 55 (LCD = 55). You will get

11W + 5*(28-W) = 5*55,

11W + 140 - 5W = 275,

6W = 275 - 140 = 135  --->  W = 135%2F6 = 22.5.


Answer.  He walked 22.5 kilometers.

Solved.