English Unlimited HTL 1, Schulbuch mit Audio-CD und CD-ROM

72 Work and leisure 06 LANGUAGE SKILLS EXPLORE LOOK AGAIN EXTRAS :RUN LQ $ % SDLUV $ UHDG DORXG WKH FDOFXODWLRQV EHORZ % ZULWH WKHP LQ \RXU H[HUFLVH ERRN DQG FDOFXODWH WKH UHVXOW 7KHQ % UHDG DORXG WKH FDOFXODWLRQV RQ S DQG $ ZULWH WKHP GRZQ DQG VROYH WKHP 28 29 30 Equations An equation is the mathematical way of saying: everything on the left of the equals sign is equal to everything on the right of the equals sign. (TXDWLRQV ZLWK GLVWDQFH VSHHG DQG WLPH Distance = Speed ×Time Time = Distance ÷ Speed Speed = Distance ÷ Time Example: John walks from school to his home on the outskirts of town at a steady speed of 4.5 km/h (kilometres per hour). It takes him 2 hours. How far does John walk? ´ In the first hour he walks 4.5 km, so in two hours he walks 9 km. Distance = Speed ×Time ´ Distance = 4.5 × 2 = 9 km Example: John jogs from 3.45 pm until 4.15 pm at an average speed of 8 km/h. What distance does he cover? ´ )LUVW ZH QHHG WR NQRZ KRZ ORQJ KH MRJV SP ļ SP PLQXWHV $V WKH VSHHG LV JLYHQ in km/h, the time must be given in hours too. 30 minutes = 0.5 hours. Now we can solve the equation. Distance = Speed ×Time ´ Distance = 8 × 0.5 = 4 ´ John jogs 4 km. :RUN LQ SDLUV DQG VROYH WKH IROORZLQő SUREOHPV 1 Phil cycles at an average speed of 24 km/h. How far does he travel if he cycles for 1.5 hours? 2 The sports ground is 3 kilometres away from Marc’s home. He usually runs at a speed of 12 km/h. How long does it take Marc to reach the sports ground? 3 How fast is a train if it travels 243 kilometres in 2 hours and 15 minutes? 6ROYH WKH IROORZLQő SUREOHP 7KHQ H[SODLQ WR D SDUWQHU KRZ \RX ZHQW DERXW LW Two people cycle for two days. On the second day they cycle for 2 hours longer and at an average speed of 5 km/h faster than they cycle on the first day. If, during the two days, they cycle a total of 180 kilometres and spend a total of 14 hours cycling, what is their average speed on the first day? TIP: Be careful with the units used in such calculations: they need to correspond with each other! 1 24 ļ 5 × 4 + 2 × 3 = 2 3 4 [(4 ] 2) × 14] ÷ 2 = 5 6 30 10 + =2 2 + = 1 4 1 8 3 ń (134 ļ 9) = (2 + 3) ×2 (5 ] 4) ×2 = Nur zu Prüfzwecken – Eigentum des Verlags öbv