A-boy-has-to-cover-4km-to-catch-a-bus-He-walks-part-of-the-distance-as-3km-h-and-run-the-rest-at-5km-h-if-he-takes-1hour-to-complete-the-distance-For-how-many-kilometres-does-he-walk-

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Question Number 75426 by otchereabdullai@gmail.com last updated on 10/Dec/19

$$\mathrm{A}\mathrm{boy}\mathrm{has}\mathrm{to}\mathrm{cover}4\mathrm{km}\mathrm{to}$$$$\mathrm{catch}\mathrm{a}\mathrm{bus}.\mathrm{He}\mathrm{walks}\mathrm{part}\mathrm{of}\mathrm{the}$$$$\mathrm{distance}\mathrm{as}3\mathrm{km}/\mathrm{h}\mathrm{and}\mathrm{run}\mathrm{the}\mathrm{rest}\mathrm{at}$$$$5\mathrm{km}/\mathrm{h}\mathrm{if}\mathrm{he}\mathrm{takes}1\mathrm{hour}\mathrm{to}\mathrm{complete}$$$$\mathrm{the}\mathrm{distance}.\mathrm{For}\mathrm{how}\mathrm{many}\mathrm{kilometres}$$$$\mathrm{does}\mathrm{he}\mathrm{walk}$$

Answered by MJS last updated on 10/Dec/19

$$\frac{x\mathrm{km}}{3\frac{\mathrm{km}}{\mathrm{hr}}}+\frac{(4-x)\mathrm{km}}{5\frac{\mathrm{km}}{\mathrm{hr}}}=1\mathrm{hr}$$$$\frac{x\mathrm{hr}}{3}+\frac{(4-x)\mathrm{hr}}{5}=1\mathrm{hr}$$$$\frac{x}{3}+\frac{4-x}{5}=1$$$$5x+3(4-x)=15$$$$2x=3$$$$x=\frac{3}{2}$$$$\mathrm{he}\mathrm{walks}1.5\mathrm{km}$$

Commented by otchereabdullai@gmail.com last updated on 11/Dec/19

$$\mathrm{Thank}\mathrm{you}\mathrm{prof}\mathrm{mjs}$$

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