How do you figure out that if the sum of two whole numbers between 20 and 40 is 58 and if the difference of the two numbers is 12 what are the two numbers?

Answer 1

Start with the difference. the first number between 20 and 40 is 21. Addin 12 gives the second number of the pair, 33. The second in the series will be 22 and 34. Write the complete series down(There are only another 5 pairs. Now see which of them totals 58, and you have your answer. The above contributor suggests solving the problem through inspection. That solution in this case may be quicker than using Algebra. There is nothing wrong with the above, except that with other parameters, that solution may be very inconvenient. Here's another approach. X + Y = 58 Y - X = 12 These two equations are given. You can't solve for two variables at once in one equation, but you can solve for one variable, and the value of one variable will be expressed "in terms of the second variable". Here's how that will help us. Y = 12 + X, by subtracting X from both sides of the second equation. Now, we can plug our new value for Y into the first equation: X + (12 + X) = 58, or: 12 + 2X = 58 12 + 2X = 58 2X = 46 X = 23 Now, 23 + Y = 58 Y = 35. 23 + 35 = 58 35 - 23 = 12. There is apparently only one solution; giving the limits of 20 and 40 was just a smokescreen. my math teacher has a bad lisp