2-3 How much longer does it take?

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SUMMARY

The discussion centers on calculating travel time differences between San Diego and Los Angeles based on varying speeds. Driving at an average speed of 105 km/h takes 2 hours and 20 minutes, covering a distance of 245 km. In contrast, driving at a reduced speed of 70 km/h results in a travel time of 3.5 hours. Consequently, the longer travel time at the slower speed is determined to be 1 hour and 10 minutes longer than the faster speed.

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karush
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You normally drive on the freeway between San Diego and Los Angel es at an average speed of $105 \, km/h \, (65 \, mi/h)$ and the trip takes $2h$ and $20 \, min$
On a Friday afternoon, however, heavy traffic slows you down and you drive the same distance at an average speed of only
$70 km/h \, (43 mi/h)$
How much longer does it take?
$d_1=r_1t_1=\dfrac{65\,mi}{\cancel{ h }} \cdot 2.33\, \cancel{h}=151.45\,mi$
$t_2=\dfrac{d_1}{r_2}=151.45\,\cancel{mi}\cdot\dfrac{h}{43\,\cancel{mi}}=3.52\,h$
$t_\Delta=t_2-t_1=3.52h-2.33h\approx 1.19\, h \approx 1\, h\, 10\, min$

ok I still get ? with these word problems so...hopefully
 
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Driving at 105 km/hr it takes 2 hours and 20 minutes= 2 and 1/3 hours= 7/3 hours to drive from San Diego to Los Angeles. So how far is it from San Diego to Los Angeles? How long will it take to drive from San Diego to Los Angles at 70 km/h?
 
Since this has been here a week now without any more response:

It takes 7/3 hours to drive at 105 km/h between San Diego and Los Angeles so they are (7/3)(105)= 7(35)= 245 km apart.

If, instead, you drive at 70 km/h it will take 245/70= 3.5 hours or 3 hours and 30 minutes. That is one hour and ten minutes longer.
 

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