The sums of n terms of two arithmetic progressions are in the ratio 5n + 4: 9n + 6. Find the ratio of their 18th terms.

Let \[a1,\text{ }a2,\text{ }and\text{ }d1,\text{ }d2\]be the initial terms and the normal distinction of the first and second math movement individually.

Then, at that point, from the inquiry we have