# 2-3 How much longer does it take?

• MHB
Gold Member
MHB
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