Моторная лодка за 8 часов проплыла 45 км против течения и вернулась обратно. Найди скорость моторной лодки в стоячей воде, если скорость течения реки равна 3 км/час.
Скорость моторной лодки в стоячей воде v км/час
Скорость моторной лодки против течения (v-3) км/час
Скорость моторной лодки по течению (v+3) км/час
Время затраченное на путь против течения 45/(x-3) час
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPA M
SPA M
SPA M
SPA M
SP A M
SP A M
SP A M
SP A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P AM
S P AM
S P AM
S P AM
S PAM
S PAM
S PAM
S PAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
S PAM
S PAM
S PAM
S PAM
S PAM
S P AM
S P AM
S P AM
S P AM
SP AM
SP A M
SP A M
SP A M
SP A M
SPA M
SPA M
SPA M
SPA M
SPA M
SPAM
SPAM
MSPA
AMSP
PAMS
SPAM
MSPA
AMSP
PAMS
SPAM
MSPA
AMSP
PAMS
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SPAM
SAM
AM
AMP
AMSP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AMSP
ASP
SP
SPM
SPAM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SPAM
SAM
AM
AMP
AMSP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AMSP
ASP
SP
SPM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
Must Waste More Time...
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPA M
SPA M
SPA M
SPA M
SP A M
SP A M
SP A M
SP A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P A M
S P AM
S P AM
S P AM
S P AM
S PAM
S PAM
S PAM
S PAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
S P AM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
S PAM
S PAM
S PAM
S PAM
S PAM
S P AM
S P AM
S P AM
S P AM
SP AM
SP A M
SP A M
SP A M
SP A M
SPA M
SPA M
SPA M
SPA M
SPA M
SPAM
SPAM
MSPA
AMSP
PAMS
SPAM
MSPA
AMSP
PAMS
SPAM
MSPA
AMSP
PAMS
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SPAM
SAM
AM
AMP
AMSP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AMSP
ASP
SP
SPM
SPAM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SP AM
SPAM
SAM
AM
AMP
AMSP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AM SP
AMSP
ASP
SP
SPM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
SPAM
Must Waste More Time...
12 км/час
Объяснение:
Моторная лодка за 8 часов проплыла 45 км против течения и вернулась обратно. Найди скорость моторной лодки в стоячей воде, если скорость течения реки равна 3 км/час.
Скорость моторной лодки в стоячей воде v км/час
Скорость моторной лодки против течения (v-3) км/час
Скорость моторной лодки по течению (v+3) км/час
Время затраченное на путь против течения 45/(x-3) час
Время затраченное на путь по течению 45/(x+3) час
45/(x-3)+45/(x+3)=8
(x-3)(x+3)(45/(x-3)+45/(x+3))=8(x-3)(x+3)
45(x+3)+45(x-3)=8(x²-9)
45x+135+45x-135=8x²-72
8x²-90x-72=0
4x²-45x-36=0
D=2025+576=2601=51²
x₁=(45-51)/8=-3/4<0
x₂=(45+51)/8=12 км/час