These questions are classic. They are a variant on the Two Cars Algebra problem. Just remember this formula: Distance = Velocity * Time Step 1) Plug in the numbers and put an "N" for your unknown variable: 900 = N * 16 Step 2) Do the easy math (PEMDAS) first: 900 = 16N Step 3) Solve for "N" by dividing both sides by 16: 900/16 = 16N/16 Step 4) Solved! Your answer should have been 56.25 = N Now we have the hidden number of 56.25. That is the velocity. Let's just use the same algebra equation again (Distance = Velocity * Time), except that now Time is the unknown variable: 400 = 56.25 * N 2) 400 = 56.25N 3) 400/56.25 = 56.25N/56.25 4) You can finish this one yourself. Here is a hint: Don't be frightened by a repeating decimal! Whether you use a vinculum or round up/down is up to your teacher. You could use a fraction but the units would not match, thus making it incorrect. I hope this was of help to you! If anybody has an easier way or any corrections, please feel free to post because I enjoy learning as well.
Assuming the speed is constant, then we can set this up in a ratio of the distance over time (miles/hours) 900 miles/16 hours = 400 miles/x hours Since we want to solve for x, multiply both sides by x: (x) (900 miles/16 hours) = 400 miles Now multiply both sides by 16 and divide by 900: x = (400)(16)/900 = 7.111 hours or 7 1/9 hours
John R. | John R: Math, Science, and History TeacherJohn R: Math, Science, and History Teach...
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This is a proportion problem. Set up the proportion so that miles/hours equals miles/hours
900/16 = 400/x 900 miles per 16 hours equals 400 miles per unknown number of hours
16x(900/16) = 16x(400/x) Cross multiply (multiply each fraction by both denominators)
900x = 6400 Simplify
900x/900 = 6400/900 Divide each side by 900
x = 64/9 Simplify the fraction
It will take about 7.11 hours or 7 hours and 7 minutes.