math
posted by alicia .
need help.
Young salmon hatch in freshwater steams and then migrate downstream to the ocean at the rate of 70 miles in 8 hours. there they live until they reach spawning age. then they return upstream to fresh water to spawn and usually die soon after. on the upstream trip, the salmon travel about 58 miles in 8 hours. find the rate of the salmon swimming in still water and the rate of the current.
this is what I have so far, but it doesnt add up
r*t=d
downstream= 8(x+y)=70
upstream=8(xy)=58

OK, it looks like you have chosen x for the rate in still water and y for the speed of the current. The equations you should have written are:
x + y = 70/8
x  y = 58/8
which is the same as you have written.
Adding them gives
2x = 128/8 = 16
x = 6 mph
y = 70/8  6 = 2.75 mph
You started the problem correctly and only needed to finish.
Respond to this Question
Similar Questions

word problem
A motor boat took 4 hours to make a downstream trip with a current of 3mph. The return trip against the same current took 8 hours. Find the speed of the boat in still water. Call Y the boat's rate. distance = rate x time. downstream … 
algebra
A boat's crew rowed 13.5 miles downstream, with the current, in 1.5 hours. The return trip upstream against the current covered the same distance, but took 4.5 hours. Find the crew's rowing rate in still water and the rate of the current. 
Algebra. Please help(:
The time required for a trip 108 miles downstream on a steamer is 3 hours less than the time required for the upstream trip. A boat whose rate is 6 miles per hour less than that of the steamer required 9 hours more for the upstream … 
Algerbra
A boat's crew rowed 10.5 miles downstream, with the current, in 1.5 hours. The return trip upstream, against the current, covered the same distance, but took 3.5 hours. Find the crew's rowing rate in still water, and the rate of the … 
math
A salmon has to swim 25 miles upstream. It swims 7 miles each day and drifts back 5 miles each night. How may days it take for the salmon to first reach 25 mile mark? 
math
A salmon has to swim 25 miles upstream. It seems 7 miles each day and drifts 5 miles at night. How many days does it take for the salmon to first reach the 25 mile mark? 
Algebra
The time required for a trip 108 miles downstream on a steamer is 3 hours less than the time required for the upstream trip. A boat whose rate is 6 miles per hour less than that of the steamer required 9 hours more for the upstream … 
algebra 2
the barge travels upstream 75.5 miles to the factory and then back to the warehouse.the barge travels upstream at a rate of 5 miles per hour slower than it travels downstream.the barge total time is 15 hours.what is the rate the barge … 
math
a boat travels 10 miles upstream in 4 hours. the boat travels the same distance downstream in 2 hours. Determine the rate of boat in still water and the rate of the current? 
Math
A salmon swims 15 miles downstream from its birth to the ocean in 3 hours. The return trip upstream to spawn takes 5 hours. How fast does the salmon swim in still water?