Anonymous
Anonymous asked in Education & ReferenceHomework Help · 7 years ago

Please someone help me with a math problem? solving for how many seats total in a theater?

Help :( I tried to draw it out lol but its confusing me still

A theater has 11 seats in the first row. each row has 3 more seats than the row in front of it.

if the theatre has 35 rows, how many seats in total are in the theatre?

Update:

really?? that was easy. (to the first answer)

Update 2:

I figured the first answer couldn't be right lol.

Something wasn't making sense.

thanks.

Relevance
• 7 years ago

The first answer is very wrong because by taking 11 + 3*35

that would mean there's just one row with 11 seats while the other 35 rows have only 3 seats each.

The number of seat per row is 11 + 3*(n-1) with n is the number of row.

For example:

First row: n=1 => seats = 11+3*(1-1) = 11

So on, the number of seats for the:

Second row = 11 + 3*1

Third row = 11 + 3*2

....

...

35th row = 11 + 3*34

The total seats in the theatre is determined as the sum of seats in all rows which is:

First row + second row + ....+ 35th row

= 11*35 + 3*(1+ 2 + 3 +....+34)

= 385 + 3*[ (1+34) + (2 + 33) +....+ (16+17)]

= 385 + 3*[ (35) + (35) + ....+ (35)]

that makes "35" repeating 16 times

= 385 + 3*16*35

= 385 + 1680

= 2065

Conclusion: if the theater has 35 rows, there'll be 2065 seats.

• 7 years ago

That other guy is wrong by the way, you don't do 11 + 3 x 35, or that just means there are 14 seats in every row. The answer is 487, because you do (11 + 3)35 - 3, -3 being 34 and not counting the first one, because it does not have an extra 3 seats.

• 7 years ago

490 seats

you do 11 + 3 X 35 = 490

Source(s): i am smart