Problem Solving

Question

The sum of the speeds of two trains is 726.7 miles per hour. If the speed of the first train is 9.3 mph faster than the second train, find the speeds of each.

Answer 1

Any time you have a word problem, start with what they tell you. According to what's been given, we have:

Sum = 726.7

Train1 = Train2 + 9.3

Train2 = ? Not given

"If you know it's something, but don't have a number, put a variable instead." This is what I tell all of my students.

Train1 = x + 9.3

Train2 = x

Since it's "sum", we'll be adding Train1 and Train2.

Sum = Train1 + Train2 <--- Substitute your values and variables here

726.7 = (x + 9.3) + (x) <---- Combine like terms

726.7 = 2x + 9.3

At this point, solve for x.