posted by Heather on .
Consider the numbers 1,2,3, and 5.
If the same numer is added to each of the numbers, it is found that the ratio of the first new number to the second is the same as the ratio of the third new number to the fourth. Find the number. Please help... I do not know how to set this up.
Let x be the number you want to find.
(x+1)/(x+2) = (x+3)/(x+5)
Multiply that out to get
x^2 + 6x + 5 = x^2 + 5x + 6
Cancel out the x^2 terms. Solve for x. Pretty easy.