Question 418987
Let {{{d}}} = distance to island from harbor
given:
Trip to island:
{{{ d = 20*t1}}}
Trip back:
{{{d = 10*t2}}}
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{{{t1 + t2 = 3}}}
This is 3 equations and 3 unknowns,
so it's solvable
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{{{t1 = d/20}}}
{{{t2 = d/10}}}
and
{{{d/20 + d/10 = 3}}}
{{{d + 2d = 60}}}
{{{3d = 60}}}
{{{d = 20}}}
The island is 20 miles from the harbor
check:
{{{20 = 20*t1}}}
{{{t1 = 1}}}
and
{{{20 = 10*t2}}}
{{{t2 = 2}}}
{{{1 + 2 = 3}}}
OK