17 A tourist was planning a trip by car for travelling at some constant speed for 2.5 hours. However, he found that if he increases the speed by 20 km/h he can cover the same distance in 30 minutes less time than it was planned. What was the planned speed of the tourist, in km/h?

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Cutie

2 February, 21:18

17 A tourist was planning a trip by car for travelling at some constant speed for 2.5 hours. However, he found that if he increases the speed by 20 km/h he can cover the same distance in 30 minutes less time than it was planned. What was the planned speed of the tourist, in km/h?

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Zackery Yu · Answer 1

Amount of time=2.5 hours

Amount of time after speed increase=2 hours

Let x=the initial speed

Let t=the amount of hours

Let y=the new speed

Let z=distance

Therefore XT=z

YT=z

Plugging everything in,

X (2.5) = z

Y (2) = z

Using substitution

Y=20+x

2.5x=z

(20+x) (2) = z

40+2x

.5x=40

X=80

Y=x+20

Y=100