How is 3n+3 is divisible by 3

n + 1

Step-by-step explanation:

Consider the division in fractional form, that is

← factor out 3 from each term on the numerator

= ← cancel common factor 3 on numerator/ denominator, leaving

= n + 1

113 seats in 18th row.

Step-by-step explanation:

number of seats in first row are 11 seats,

there are increment of 6 seats in every next row, so this is arithmetic series,

so we can use the formula of arithmetic series’s nth term :

a(n) = a(1) +(n-1)d

seats in 18th row, so given values are a(1) = 11, n=18, and d=6

a(18) = 11+(18-1)(6)

a(18) = 11+17*6

a(18) = 11+102

a(18) = 113

So there are 113 seats in 18th row.