In a music stadium, there are 18 seats in the first row and 21 seats in the second row. the number of seats in a row continues to increase by 3 with each additional row.

(a) write an explicit rule to model the sequence formed by the number of seats in each row. show your work.

(b) use the rule to determine which row has 120 seats. show your work.

  (a) an = 18 +3(n -1)

  (b) row 35

Step-by-step explanation:

(a) The general term (an) of an arithmetic sequence can be expressed in terms of the first term (a1) and the common difference (d) as ...

  an = a1 +d(n -1)

The given sequence has a1 = 18 and d = 3, so the explicit formula is ...

  an = 18 + 3(n -1)

__

(b) We want to find n such that an = 120.

  120 = 18 + 3(n -1)

  40 = 6 + n - 1 . . . . . . . divide by 3

  35 = n . . . . . . . . . . . . . subtract 5

Row 35 has 120 seats.

the inequality is:

250c+180g≥950

step-by-step explanation:

let c denotes the number of days in a week   miyoko worked as a cryptographer.

and g denotes the number of days in a week she works as a geologist.

now we are given that she earns $250 for every day she works as a cryptographer,and earns $180 for every day she works as a geologist.

now miyoko's goal is to earn more than $950 this week.

hence, the inequality could be represented as:

250c+180g≥950

answer: 1722

step-by-step explanation:

given: the mass of saturn=

the mass of mercury=

the number of times the mass of saturn is greater than the mass of mercury

hence, the mass of saturn is 1722 times greater than the mass of mercury.