SOLUTION: I traveled 180 km at the speed of 45 km/hr and arrived 15 minutes late. at what speed in (km/hr) should i have traveled to arrive on time? A)40 B)43 C)44.5 D)48

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Question 879122: I traveled 180 km at the speed of 45 km/hr and arrived 15 minutes late. at what speed in (km/hr) should i have traveled to arrive on time?
A)40
B)43
C)44.5
D)48
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = your speed to arrive on time in km/hr
Let +t+ = your elapsed time to arrive on time in hrs
------------------------
(1) +180+=+s%2At+
(2) +180+=+45%2A%28+t+%2B+1%2F4+%29+ ( note that 15 min = 1/4 hr )
--------------------------
(2) +180+=+45t+%2B+45%2F4+
(2) +720+=+180t+%2B+45+
(2) +180t+=+675+
(2) +t+=+3.75+
and
(1) +180+=+s%2A3.75+
(1) +s+=+180%2F3.75+
(1) +s+=+48+
My answer is (D), 48 km/hr