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-

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

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

Answered by MJS last updated on 10/Dec/19

$$\frac{{x}\mathrm{km}}{\mathrm{3}\frac{\mathrm{km}}{\mathrm{hr}}}+\frac{\left(\mathrm{4}−{x}\right)\mathrm{km}}{\mathrm{5}\frac{\mathrm{km}}{\mathrm{hr}}}=\mathrm{1hr} \\ $$$$\frac{{x}\mathrm{hr}}{\mathrm{3}}+\frac{\left(\mathrm{4}−{x}\right)\mathrm{hr}}{\mathrm{5}}=\mathrm{1hr} \\ $$$$\frac{{x}}{\mathrm{3}}+\frac{\mathrm{4}−{x}}{\mathrm{5}}=\mathrm{1} \\ $$$$\mathrm{5}{x}+\mathrm{3}\left(\mathrm{4}−{x}\right)=\mathrm{15} \\ $$$$\mathrm{2}{x}=\mathrm{3} \\ $$$${x}=\frac{\mathrm{3}}{\mathrm{2}} \\ $$$$\mathrm{he}\:\mathrm{walks}\:\mathrm{1}.\mathrm{5km} \\ $$

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

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

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