Express the average age of three sisters in the terms of the age a of the firstborn (in years) if the second was born 4 years after the first and the third was born 6 years after the second.

arithmetic sequence

step-by-step explanation:

given that a sequence has terms as

19, 15, 11,

this is represented on a graph

the pattern indicates that the sequence is an arithmetic sequence with i term

a=19 and common difference d =-4

any general term

thus the sequence is reduced by 4 for each successive term starting from 1 and nth term is

24-5n.

first negative term would start after 5th term

5th term =24-25< 0

from 5th term onwards the sequence would be negative.

468

step-by-step explanation:

4400

step-by-step explanation: