## Megichu 3 years ago the front row of a stadium has 25 seats. each of the other rows has two more seats than the row in front of it. how many seats are there altogether in the first 20 rows?

1. timo86m

25+(x*2)

2. Megichu

oh wow, thanks for the quick response!

3. timo86m

not finished

@timo86m :can u explain how did u get that ?

5. Megichu

im studying for the SATs and am struggling greatly with permutations

6. Megichu

sequences*

@Megichu : U know A.Sequence basics ?

8. timo86m

2+2+2+2...=19*2 =38 25+(19*25)+38

9. Megichu

i understand what the basic formula is, but interpreting the problem at times can be difficult

10. timo86m

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Front row=a=first term=25. Each of the other rows has two more seats than the row in front of it ,thats mean that the difference between every two rows is 2 ,So d=2 ========================= a=25 ,d=2 Sum law : Sn=n/2[2a+(n-1)d] where n = number of terms .. now lets fill up the rule S20=20/2 [2*25+(20-1)2]=880 seats . ------------------------------------------------------------- Make sense ?

12. Megichu

perfect. thank you so much for the great response! and yes, that makes much more sense

Great,Inform me when you need help :)

14. Megichu

not sure why i have such a difficult time with these problems (considering that their are 2 main formulas XD) but i really appreciate the help

15. Megichu

also, this site is great. i look forward to using it more often!

Just keep solving examples ,Then it will get much easier :)

17. Megichu

definitely doing a lot of that right now! haha im taking an SAT course right now and have a packet to practice all of these lovely problems :3