Vintage US Postcards

Where should I land my boat?

I am in a boat 2 miles offshore. I need to get home which is 6 miles down a straight shoreline. I can walk 5mph and can row 2mph. Where should I land onshore to get home the quickest?
12 minutes ago - 3 days left to answer.

say you land x miles from the shore where you are now.

your total path is the hypoteneuse of a right triangle whose legs are 2 and x (for rowing) plus a remainder of 6-x (for walking)

so the time spent is sqrt(x^2+4)/2 + (6-x)/5
to minimize time, set the derivative =0
x/(2sqrt(x^2+4)) - 1/5 = 0
x/2 = sqrt(x^2+4)/5
5x = 2sqrt(x^2+4)
square both sides
25x^2 = 4x^2 + 16
x = sqrt(16/21) = 4/21 sqrt(21)

BOAT LANDING CENTRE HARBOR NEW HAMPSHIRE 1906 POSTCARD $7.99 Time Remaining: 3h 50m Buy It Now for only: $7.99

1950s Sanibel Captiva FL Mail Boat at Captiva Landing Postcard $3.75 Time Remaining: 3h 55m Buy It Now for only: $3.75

MilfordNE Camp Kiwanis Boat Landing on Big Blue River $4.88 Time Remaining: 4h 36m Buy It Now for only: $4.88

NY LEWISTON BOAT LANDING postcard $1.99 Time Remaining: 4h 42m Buy It Now for only: $1.99

c1950 BOAT LANDINGGULL LAKE DANBURYWI RPPC POSTCARD $10.00 Time Remaining: 4h 44m Buy It Now for only: $10.00

Boat Landing Boat Houses ABSECON NJ ca1908 $11.95 Time Remaining: 4h 51m Buy It Now for only: $11.95

FL TAMPA SULPHUR SPRINGS BOAT LANDING EARLY R37007 $15.00 Time Remaining: 5h 10m Buy It Now for only: $15.00

NJ HOLLY BEACH THE BOAT LANDING 1907 postcard $2.19 Time Remaining: 5h 30m Buy It Now for only: $2.19

PA WILLIAMSPORT BOAT LANDING 1909 postcard $2.99 Time Remaining: 5h 56m Buy It Now for only: $2.99

SQUIRREL ISLAND ME LOT OF 2 BOAT LANDING OLD BOATS CLEFT ROCK CIRCA 1907 $2.50 Time Remaining: 8h 30m

4 Indian Lake Michigan WIESTS LANDING Shoreline Boats 1910 era Postcards $18.00 Time Remaining: 8h 53m Buy It Now for only: $18.00

Boat Landing Pass A Grille Florida FL Old Postcard Vintage Pinellas County $12.99 Time Remaining: 8h 58m Buy It Now for only: $12.99

Boat Landing and Miller Tower Chautauqua Lake NY Postcard 1920 $1.60 Time Remaining: 11h 12m Buy It Now for only: $1.60

RI NEWPORT BOAT LANDING ESTATES homes postcard $2.49 Time Remaining: 11h 26m Buy It Now for only: $2.49

Boat Landing Ortonville Minnesota PC408 $4.00 Time Remaining: 11h 32m Buy It Now for only: $4.00

NY LONG ISLAND SEA CLIFF Boat Landing postcard $9.99 Time Remaining: 11h 39m Buy It Now for only: $9.99

NY OAK ISLAND Boat Landing Pier 1909 postcard $15.99 Time Remaining: 12h 15m Buy It Now for only: $15.99

MARIPOSA COUNTY CA Boat Landing Oakvale Ranch Postcard $19.99 Time Remaining: 12h 31m Buy It Now for only: $19.99

Sandusky Ohio Cedar Point Boat Landing 1910s Colored Postcard $7.50 Time Remaining: 13h 26m

Lake Winnepesaukee NH 1906 Boat Landing Centre Harbor $12.50 Time Remaining: 14h 17m Buy It Now for only: $12.50

PROVINCETOWN CAPE COD MA BOAT LANDING and RAILROAD SQUARE 1936 $4.00 (1 Bid) Time Remaining: 14h 22m

LITTLE YORK LAKE NY BOAT LANDING VINTAGE PC $6.99 Time Remaining: 14h 47m Buy It Now for only: $6.99

Steam Boat Landing Peoria IL old 1900s Postcard $6.30 Time Remaining: 15h 9m Buy It Now for only: $6.30

1907 STEAMER BOAT LANDING CHAUTAUQUA ILLINOIS POSTCARD $19.00 Time Remaining: 15h 48m Buy It Now for only: $19.00

Willimantic CT Boat Landing 1910 Ladies in Rowboat $9.99 Time Remaining: 16h 5m Buy It Now for only: $9.99

Lewiston New York BOAT LANDING 1910 Postcard $7.00 Time Remaining: 16h 58m Buy It Now for only: $7.00

1906 CANOE BOATS LANDING Willow Grove Park PHILADELPHIA Pennsylvania PA y2285 $16.95 Time Remaining: 17h 27m

1903 STEAMER BOAT LANDING in Alton Bay NH card z730 $6.00 Time Remaining: 19h 28m

Postcard ST PAULMinnesotaMN COMO AMUSEMENT PARK BOAT LANDING view 1906 $9.99 Time Remaining: 1d 1h 3m Buy It Now for only: $9.99

0412 HOLYOKE MA VINTAGE PC BOAT LANDING HAMPTON PONDS 1910 BOATS ROWBOATS $8.39 Time Remaining: 1d 1h 44m Buy It Now for only: $8.39

Willow Grove Park Pa Boat landing canoes buildings bridge old postcard $0.35 (1 Bid) Time Remaining: 1d 4h 41m

MEMPHIS TENNESSEE RIVERSIDE PARK BOAT LANDING ANTIQUE VINTAGE POSTCARD TRINIDAD $13.99 Time Remaining: 1d 4h 49m Buy It Now for only: $13.99

BOAT LANDING KELLEYS ISLAND OHIO ON LAKE ERIE BOAT MASCOT AT DOCK OH O $1.99 (1 Bid) Time Remaining: 1d 5h 3m

CHEBEAGUE ISLAND ME Central Boat Landing Old Postcard $9.91 Time Remaining: 1d 5h 14m Buy It Now for only: $9.91

Boat Landing from South Shore Chautauqua Institution NY $5.50 Time Remaining: 1d 5h 17m Buy It Now for only: $5.50

CEDAR POINT OHIO Boat Landing 1913 Postcard $9.00 Time Remaining: 1d 5h 26m Buy It Now for only: $9.00

PAVILION BOAT LANDING GARDEN GARFIELD PARK CHICAGO IL $21.97 Time Remaining: 1d 6h Buy It Now for only: $21.97

1908 CENTRE HARBORNH BOAT LANDING HOMES Belknap GW MORRIS Moultonborough $4.00 Time Remaining: 1d 6h 2m

Skaneateles NY TOUR BOAT LANDING Postcard $15.50 Time Remaining: 1d 6h 24m Buy It Now for only: $15.50

Rockland Lake NY BOAT LANDING AT SOUTH END Postcard $10.00 Time Remaining: 1d 6h 27m Buy It Now for only: $10.00

Echo Lake Boat Landing New Hampshire C1910 RPPC $5.89 Time Remaining: 1d 7h 21m Buy It Now for only: $5.89

Lake George NY Boat Landing Adirondack Mts Postcard $5.50 Time Remaining: 1d 7h 56m Buy It Now for only: $5.50

MS GREENVILLE CONCRETE BOAT LANDING MAILED 1920 T65849 $15.00 Time Remaining: 1d 8h 6m Buy It Now for only: $15.00

BOAT LANDING ELECTRIC PARK HIGHLAND WINSTED CT 1907 pc $9.99 Time Remaining: 1d 8h 17m Buy It Now for only: $9.99

Louisiana LA New Orleans Lugger Boat Landing 1905 Postcard $5.95 Time Remaining: 1d 8h 47m Buy It Now for only: $5.95

1911 SAN FRANCISCO CA BOAT LANDING STOW LAKE GOLDEN STATE PARK FN VF $9.50 Time Remaining: 1d 9h 5m

Boat Landing Lake Cisco Cisco Texas 1927 $9.99 Time Remaining: 1d 9h 11m Buy It Now for only: $9.99

Sterling JunctionMA 1914 Breezy Point Stboat Landing $11.00 Time Remaining: 1d 9h 19m Buy It Now for only: $11.00

New Orleans LA Luggar Landing Boats Ships 1906 Postcard $6.00 Time Remaining: 1d 10h 20m Buy It Now for only: $6.00

Postcard Indian Lake OHIO Boat Landing view 1930s $9.99 Time Remaining: 1d 13h 32m Buy It Now for only: $9.99

PC Buckeye Lake OHIO Private Boat Landing view 1907 $9.99 Time Remaining: 1d 13h 32m Buy It Now for only: $9.99

BOAT LANDING CLEVELAND OHIO VINTAGE LINEN POSTCARD $5.95 Time Remaining: 1d 14h 6m Buy It Now for only: $5.95

Boat Landing State Waiting Room Nantasket Beach MA 1959 Massachusetts $4.75 Time Remaining: 1d 14h 22m

WINSTED CT Highland Lake Electric Park Boat Landing c1905 Postcard $6.89 Time Remaining: 1d 14h 23m Buy It Now for only: $6.89

MA WEBSTER BEACON PARK BOAT LANDING 1933 postcard $3.59 Time Remaining: 1d 14h 35m Buy It Now for only: $3.59

Boat Landing Bar Harbor ME Maine $22.49 (5 Bids) Time Remaining: 1d 14h 54m

RPPC Walkers Boat Landing East Peru ME Maine $9.99 Time Remaining: 1d 14h 59m Buy It Now for only: $20.00

Westlake Village CA California Boat Landing Vn Postcard $6.00 Time Remaining: 1d 15h 28m Buy It Now for only: $6.00

New Hampshire NH Shore View at Boat Landing of Hotel Wentworth Old Postcard $0.60 Time Remaining: 1d 15h 49m

boat landing highland lake winsted connecticut postcard $7.99 Time Remaining: 1d 17h 20m Buy It Now for only: $7.99

Cooperstown NY Otsego Lake Boat Landing old postcard $6.99 Time Remaining: 1d 18h 30m Buy It Now for only: $6.99

Boat Landing On The Arkansas Fort Smith Ark Postcard $8.00 Time Remaining: 1d 18h 44m Buy It Now for only: $8.00

Jacks Boat Landing Poteau River Fort Smith Ar Postcard $8.00 Time Remaining: 1d 18h 44m Buy It Now for only: $8.00

NY Jamestown LITHO 1910 BOAT LANDING Ferries Vg+ $9.59 Time Remaining: 1d 19h 11m Buy It Now for only: $9.59

Boat Landing at Crystal Clear Silver Springs Fl Glass Bottom Boats Linen 1951 $0.99 Time Remaining: 1d 23h 31m

The Boat Landing Canobie Lake Park NH Rotograph G 25005 $5.50 Time Remaining: 2d 26m Buy It Now for only: $5.50

1913 Lakewood New Jersey Postcard View of Lake Boat Landing $4.95 Time Remaining: 2d 1h 24m Buy It Now for only: $4.95

Bunns Boat Landing Swartswood Lake Newton Stillwater NJ $12.00 Time Remaining: 2d 2h 40m

Columbus Ave Toward Boat Landing Sandusky Ohio 1922 $7.50 Time Remaining: 2d 2h 40m

Boats At Dustin Landing Taunton Massachusetts 1908 $7.50 Time Remaining: 2d 2h 42m

Boat Landing Lake Watatic Winchendon Massachusetts $7.50 Time Remaining: 2d 2h 42m

1914 NO ATTLEBORO MA Whiting Pond Boat Landing postcard $9.99 Time Remaining: 2d 3h 23m Buy It Now for only: $9.99

Taunton MA Boat Landing c1910 Postcard $2.99 Time Remaining: 2d 3h 25m Buy It Now for only: $2.99

Old Point Comfort VA Postcard Steam Boat Landing $6.95 Time Remaining: 2d 3h 54m Buy It Now for only: $6.95

Dennisville NJ Boat Landing unused c1920 postcard $4.95 Time Remaining: 2d 4h 12m