Eva swam 100m with the current in the same amount of time that it took her to swim 80m against the current. the speed of the current is 5m/min. calculate her speed if she were swimming in still water.
i don't understand how to do this question??????????
Math question? help? please?
2014-02-10 6:32 pm
回答 (2)
2014-02-10 6:56 pm
✔ 最佳答案
Let v be the speed when Eva were swimming in still watert be the time when Eva were swimming in still water
vt+5t=100-----------(1)
vt-5t=80----------(2)
(1)-(2)10t=80
t=8min
Sub t=8 to (1)
8v+5(40)=100
8v=80
v=8m/min
2014-02-10 6:54 pm
d= vt
or t= d/v
v= speed- velocity-
V her current speed = her speed S -in still water + or minus the current speed C = 5 meter per minute
with current
t1 = 100 / (S+C)
against current
t2= 80/(V-C)
since t1=t2
plug in
solve for S
or t= d/v
v= speed- velocity-
V her current speed = her speed S -in still water + or minus the current speed C = 5 meter per minute
with current
t1 = 100 / (S+C)
against current
t2= 80/(V-C)
since t1=t2
plug in
solve for S
收錄日期: 2021-05-01 15:04:05
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