Question

There are 25 rows of seats in an auditorium. The 1st row is of 20 seats, the 2nd row of 22 seats the 3rd row of 24 seats and so on. How many seats are there in 21 st row? ​

Answer 1

$\bf\large\underline\pink{Answer:-}$

20 + 22 + 24 + .......... 25 terms

These are in AP

a = 20

n= 25

d = 2

nth term in AP Tn = a + (n-1)d

✓✓✓

nth term = 20 + (25-1)2 = 20+(24×2) = 20+48 = 68

✓✓✓✓✓ In 21st row there will be 68 seats ✓✓✓✓✓

Answer 2

Answer:

1,625

Step-by-step explanation:

add em all

65×25

=1,625