SOLUTION: The distance between Morehead and Lexington is approximately 60 miles. In your travel you experience no traffic or road construction. How much time would you save by speeding jus

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: The distance between Morehead and Lexington is approximately 60 miles. In your travel you experience no traffic or road construction. How much time would you save by speeding jus      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 938123: The distance between Morehead and Lexington is approximately 60 miles. In your travel you experience no traffic or road construction. How much time would you save by speeding just a little bit, traveling at a constant 75 mph instead of the posted 70 mph? Then solve the problem and write down how you solved it. State your answer as ___min & ___sec.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
At +70+ mi/hr:
+60+=+70t+
+t+=+60%2F70+ hrs
-------------------
At +75+ mi/hr:
+60+=+75t+
+t+=+60%2F75+ hrs
-------------------
+60%2F70+-+60%2F75+=+60%2A%28+1%2F70+-+1%2F75+%29+
+60%2A%28+1%2F5%29%2A%28+1%2F14+-+1%2F15+%29+
+12%2A%28+1%2F14+-+1%2F15+%29+ hrs
-------------------------
Convert to minutes:
( min ) = ( hrs )*( min/hrs )
+12%2A%28+60%2F14+-+60%2F15+%29+
+12%2A%28+%28+4+%2B+4%2F14+%29+-+4+%29+
+12%2A%28+2%2F7+%29+=+24%2F7+ min
+24%2F7+=+3+%2B+3%2F7+ min
------------------------
Convert +3%2F7+ to sec
+%283%2F7%29%2A60+=+25.7+ sec
You save 3 min 26 sec
--------------------------
check:
+%28+24%2F7+%29%2F60+=+%28+6%2F7+%29%2F15+
+%28+6%2F7+%29%2F15+=+6%2F105++ hrs
--------------------------
+60%2F70+-+60%2F75+=+6%2F105+
+10%2F70+-+10%2F75+=+1%2F105+
+.142857+-+.133333+=+.0095238+
+.009524+=+.0095238+
close enough