Question 1108986: The ratio of x to y is 4:9 and the ratio of y to z is 18:15, what is the ratio of x to z? Found 2 solutions by ikleyn, greenestamps:Answer by ikleyn(52794) (Show Source):
While the algebraic method shown by the other tutor is perfectly good, I find it a bit confusing to do it that way, finding it easy to get the wrong numbers in the wrong places.
Here is how I like to do problems like this....
Since we are given the ratio of x to y and the ratio of y to z, if we can change one or both of the given ratios to equivalent ratios such that the y value is the same in both, then we can easily find the ratio of x to z.
Since the y value in the first ratio is 9 and it is 18 in the second ratio, we can double both numbers in the first ratio to make y equal to 18 in both ratios. Then the compound ratio will show us the ratio between x and z.
