<p>ok the first problem i saw and i didn't know how to do it. there's no explanation for it b/c it's not even a part of the practice tests.</p>
<p>graham walked to school at an avg speed of 3 mi/hr and jogged back along the same route at 5mi/hr. if his total traveling time was 1 hr, what was teh total number of miles in the round trip?</p>
<p>yikes. somebody? i feel stupid</p>
<p>lol this is an example question, i thought. dont they give a "joe bloggs" explanation?:</p>
<p>Let d be your distance
d/3 + d/5 = 1</p>
<p>Solve for d
5d/15 + 3d/15 = 1
8d/15 = 1
d=15/8 miles
But this is for one trip, so multiply by 2 to get 15/4 miles</p>
<p>rate x time = distance
rate1 x time1 = distance
rate2 x time2 = distance</p>
<p>... so time1/time2 = rate2/rate1</p>
<p>since time1 + time = 1 hour,
time1 = 3/8 hour
(time2 = 5/8 hour, but we don't need to know this)</p>
<p>rate1 x time1 = distance (1/2 trip)</p>
<p>3/8 hour x 5 mph = 15/8 mile</p>
<p>total = 15/4</p>
<p>sry i'm slow, but why is it "1" to the right of the equal sign? :l</p>
<p>1 is the total time to travel the whole trip, i.e. 1 hour
d/3 is the time in hours it takes to get to school walking, and d/5 is the time it takes to go back jogging</p>
<p>oh okay, thank u so much i got it now</p>