Question 1108986
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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.<br>
Here is how I like to do problems like this....<br>
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.<br>
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.<br>
x:y = 4:9 = 8:18
y:z = 18:15<br>
Therefore
x:y:z = 8:18:15<br>
So
x:z = 8:15