translate from English to Math
"If the 16th term of an arithmetic sequence is three times the fourth term"
--->a+15d = 3(a+3d)
a+15d = 3a+3d
12d = 2a
a = 6d
term 23 = a+22d = 6d+22d = 28d
term 3 = a + 2d = 6d + 2d = 8d
term23 : term3 = 28d : 8d
= 28 : 8
= 7 : 2
If the 16th term of an arithmetic sequence is three times the fourth term, find the ratio of the 23rd term to the third term.
2 answers
isn't it supposed to be 3a + 9d?
2 answers