SOLUTION: A motorboat maintained a constant speed of 15 mph relative to the water in going 10 miles upstream and then returning. The total time for this trip was 1.5 hours. Use this info to
Algebra.Com
Question 882550: A motorboat maintained a constant speed of 15 mph relative to the water in going 10 miles upstream and then returning. The total time for this trip was 1.5 hours. Use this info to find the speed of the current.
*PLEASE* help explain how I figure this out!
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
A motorboat maintained a constant speed of 15 mph relative to the water in going 10 miles upstream and then returning. The total time for this trip was 1.5 hours. Use this info to find the speed of the current.
***
let x=speed of current
15+x=speed of boat downstream
15-x=speed of boat upstream
travel time=distance/speed
total travel time=travel time upstream+travel time downstream
1.5=10/(15-x)+10/(15+x)
lcd:(15-x)(15+x)
1.5*(15-x)(15+x)=10(15+x)+10(15-x)
1.5(15^2-x^2)=150+10x+150-10x
1.5(225-x^2)=300
(225-x^2)=200
x^2=25
x=±5
speed of current=5 mph
RELATED QUESTIONS
A motorboat maintained a constant speed of 15 miles per hour relative to the water in... (answered by ikleyn)
A motorboat maintained a constant speed of 15 miles per hour relative to the water in... (answered by lwsshak3)
a motorboat maintained a constant speed of 15 miles per hour relative to the water in... (answered by ikleyn)
A motorboat maintained a constant speed of 15
miles per hour relative to the water in (answered by josgarithmetic)
word problem associated with quadratic equation chapter::
a motorboat maintained a... (answered by ankor@dixie-net.com)
A motorboat maintain a constant speed of 15 mph in the water in going 10 miles upstream... (answered by ankor@dixie-net.com)
A motorboat maintained a constant speed of 14 miles per hour relative to the water in... (answered by richwmiller)
A motorboat maintained a constant speed of 12 miles per hour relative to the water in... (answered by richwmiller)
A motorboat maintained a constant speed of
24
24 miles per hour relative to the water... (answered by ikleyn)