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leoponc · Apr 2, 2013, 07:49 AM

If one-third of a number is three less than one-half of the number, find the number.

leoponc · Apr 2, 2013, 07:56 AM

The sum of the digit of a two-digit number is 10. If the tens digit is 8 more than the one's digit, find the number

aundreaschwab · Apr 2, 2013, 10:42 AM

During the first part of a trip, a canoeist travels 28 miles at a certain speed. The canoeist travels 9 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hours. What was the speed on each part of the trip?

MacyBeee · Apr 2, 2013, 05:02 PM

leoponc: you're answer should be 18. You set it up as 1/3x=1/2x-3. first move the 1/2x to the other side by subtracting from 1/3x. You should get -1/6x=-3. from there divide -3 by -1/6, and you should get your final answer of 18.

MacyBeee · Apr 2, 2013, 05:14 PM

Originally Posted by leoponc

the sum of the digit of a two-digit number is 10. if the tens digit is 8 more than the one's digit, find the number

leoponc: you're answer to this should be 91. Your two formulas should be x+y=10 and x=y+8 (x is your tens digit and y is your ones digit). Substitute y+8 into x's place in the first formula and solve. You should get:
y+8+y=10
2y+8=10
2y=2
y=1
Then plug 1 into the second equation. You should get:
x=1+8
x=9
From there you know that the number is 91.

MacyBeee · Apr 2, 2013, 05:15 PM

Originally Posted by aundreaschwab

During the first part of a trip, a canoeist travels 28 miles at a certain speed. The canoeist travels 9 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hours. What was the speed on each part of the trip?

I don't know how you can answer this without knowing how long they traveled per section. Sorry!

ebaines · Apr 3, 2013, 05:54 AM

Originally Posted by aundreaschwab

During the first part of a trip, a canoeist travels 28 miles at a certain speed. The canoeist travels 9 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hours. What was the speed on each part of the trip?

Starting wirth the basic formula of distance = rate times time, so rearrange to get time = distance/rate. The first part of the trip consists of 28 miles at X miles per hour, and the second leg is 9 miles in x-5 hours. Set up an equation for the total time using this data, and set it equal to 3 hours. Solve for x.