A theater is designed with 15 seats in the first row, 19 in the second, 23 in the third, and so on. If this seating pattern continues, how many seats are in the 30th row?
A 127
B 131
C 135
D 139

Please show work. Thanks!

Question

A theater is designed with 15 seats in the first row, 19 in the second, 23 in the third, and so on. If this seating pattern continues, how many seats are in the 30th row?
A 127
B 131
C 135
D 139

Please show work. Thanks!

misty1212 · Answer

HI!!

misty1212 · Answer

looks like you keep adding 4 each time

misty1212 · Answer

$$1\to 15\
2\to 15+4\
3\to 15+2\times 4\
4\to 15+3\times 4\
30\to 15+?$$

directrix · Answer

@Impala_221b 

In this arithmetic sequence, try using the formula for the nth term.

n = 30 in this problem and represents the number of seats on the 30th row.

30th seat has -->  (seats in first row) + ( n - 1) * d

d is the common difference. See Misty's work above.

Crank this out and let us know what you get.

impala_221b · Answer

I got B.  Is this correct? sorry i did not reply earlier, had problems.

likeabossssssss · Answer

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