Question

A theatre has 50 seats on the front row. There are 4 additional seats in each following row.

Part A write a formula to represent the number of each seats in any given row as an explicit formula.

Part b How many seats are in the 20th row

Answer 1

`\boxed { \boxed { T_n = a_1 + d(n - 1)}}`


`\text {Given that }a_1 = 50 \text { and } d = 4`


`T_n = 50 + 4(n - 1)`


`T_n = 50 + 4n - 4`


`T_n = 46 + 4n`


`\boxed { \boxed {T_n = 46 + 4n }}`

When n = 20,

`T_(20) = 46 + 4(20) = 126`


`\boxed { \boxed {\text{Answer: The 20th term is 126}}}`