The AP 4, 9, 14, …, 249 is finite. How many terms does it have, and what is its 8th term from the…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The AP is finite. How many terms does it have, and what is its th term from the end?
Need a reminder? The key ideaShow
The th term of an AP is . A number is a term only if comes out a whole number of at least . The th term from the end of a finite AP with last term is .
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Number of terms. , so and .
Step 2. From the end. .
Step 3. Check. It is also the rd term from the start: .
Answer: terms; the th term from the end is .
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