SOLUTION: Sam leaves for the store on his skateboard at 8 mph. His skateboard breaks when he gets to the store, so he immediately goes home at a speed of 4 mph. What is the round trip distan

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Sam leaves for the store on his skateboard at 8 mph. His skateboard breaks when he gets to the store, so he immediately goes home at a speed of 4 mph. What is the round trip distan      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 675768: Sam leaves for the store on his skateboard at 8 mph. His skateboard breaks when he gets to the store, so he immediately goes home at a speed of 4 mph. What is the round trip distance if it took 2 hours?
Found 2 solutions by josmiceli, Alan3354:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = the one-way distance to store
Let +t+ = time going to store ( one-way time )
given:
(1) +d+=+8t+
(2) +d+=+4%2A%28+2+-+t+%29+
------------------
Substitute (1) into (2)
(2) +8t+=+4%2A%28+2+-+t+%29+
(2) +8t+=+8+-+4t+
(2) +12t+=+8+
(2) +t+=+2%2F3+ ( 40 minutes )
and
(1) +d+=+8t+
(1) +d+=+8%2A%282%2F3%29+
(1) +d+=+16%2F3+
+2d+=+32%2F3+
+2d+=+10.667+ miles round-trip
check answer:
(2) +d+=+4%2A%28+2+-+t+%29+
(2) +16%2F3+=+4%2A%28+2+-+t+%29+
(2) +16%2F3+=+8+-+4t+
(2) +4t+=+24%2F3+-+16%2F3+
(2) +4t+=+8%2F3+
(2) +t+=+2%2F3+
OK



Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Sam leaves for the store on his skateboard at 8 mph. His skateboard breaks when he gets to the store, so he immediately goes home at a speed of 4 mph. What is the round trip distance if it took 2 hours?
---------------
Avg speed for the round trip = 2*8*4/(8+4) = 64/12
Avg = 16/3 mi/hr
d = r*t = 2*16/3
RT distance = 32/3 miles