Question 941679
 Micaela drove from New Haven to Putnam, CT during rush hour at an average speed of 60miles per hour, and then drove back the same way at an average speed of 40miles per hour.
If the round trip took 3 hour and 45 minutes, how many miles is Micaela's one-way trip from Putnam, CT to New Haven?
:
let d = one-way distance from N.H to Put
Change 3 hr 45 min to 3.75 hrs
:
Write a time equation; time = dist/speed
:
Time to + time back = 3.75 hrs
{{{d/60}}} + {{{d/40}}} = 3.75
multiply equation by 120
120*{{{d/60}}} + 120*{{{d/40}}} = 3.75(120)
Cancel the denominators, you have
2d + 3d = 450
5d = 450
d = 450/5
d = 90 mi one way
:
;
Check this, find the actual times
90/60 = 1.5 hrs
90/40 = 2.25 hrs
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total time 3.75 hrs