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Пусть S = x
х/15+х/10 = 1
15х+10х=150
25х=150
х=6
Ответ:6 км.
h=d/sina
V=1/3ПR^2h
R=h*tga=dtga/sina=d/cosa
V=1/3Пd^3/cos^2asina=2/3Пd^3/(cosasin2a)