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Hi there! Have questions about your homework? At Brainly, there are 60 million students who want to help each other learn. Questions are usually answered in less than 10 minutes. Try it for yourself by posting a question! :D

1. One number is twice another. The sum of the reciprocal is 9/2 . Find the two numbers.

2. A boat travels 30 miles up a river in the same amount of time it takes to travel 50 miles down the same river. If the current is 5 mph, what is the speed of the boat in still water?

1. Let a=1st no. and b=2nd no. One number is twice another means "a=2(b)"..The sum of the reciprocal is 9/2 means "1/a + 1/b = 9/2".. To find the value of b, we substitute eq.1 to eq.2... So, 1/2(b) + 1/b =9/2,.. Solving this,..3/2b = 9/2... 6=18b... b=1/3... Next is the value of a... a=2(b)....a=2(1/3)...a=2/3.. Therefore the two numbers are 1/3 and 2/3. 2.

2. The equation is " time = distance/rate". The rate upstream is "(r-5 mph)"... The rate downstream is "(r+5)"... It says that the time to travel is the same, So it means " time(up) = time (down)". With these, we can now have a new equation " 30/(r-5) =50/(r+5) "..... Solve: 30r + 150 = 50r - 250... 20r=400...r = 20 mph... Therefore the speed of the boat in still water is 20 mph.