Question

An auditorium has 40 rows of seats. There are 20

seats in the first row. Each row has 2 more seats
than the row before.
Identify the number of seats in the first 4 rows:

Answer 1

98

Explanation:

Answer 2

140 seats

Explanation:

40 rows

1ˢᵗ row = 20 seats

39 next rows = 2×20 = 40 seats

First 4 rows = 20 seats + 3(40) seats = 140 seats

➪the 2ⁿᵈ, 3ʳᵈ and 4ᵗʰ rows have equal number of seats = 40 seats