Advertisements
Advertisements
प्रश्न
Which term of the A.P. 3, 8, 13, 18, … is 78?
उत्तर
3, 8, 13, 18, … is 78
Let 78 is nth term
Here, a = 3, d = 8 – 3 = 5
∴ 78 = a + (n –1)d
⇒ 78 = 3 + (n – 1)5
⇒ 78 = 3 + 5n – 5
⇒ 78 + 5 – 3 = 5n
⇒ 5n = 80
⇒ n = `(80)/(5)` = 16
∴ 78 is 16th term.
APPEARS IN
संबंधित प्रश्न
Insert six A.M.s between` 15 and -15`
Q.8
The 6th term of an A.P. is 16 and the 14th term is 32. Determine the 36th term.
The nth term of a sequence is 8 – 5n. Show that the sequence is an A.P.
Divide 216 into three parts which are in A.P. and the product of two smaller parts is 5040.
How many two digit numbers are divisible by 3?
Find the sum of last 8 terms of the A.P. –12, –10, –8, ……, 58.
Find the indicated terms in each of following A.P.s: 1, 6, 11, 16, …; a20
Find the 8th term of the A.P. whose first term is 7 and common difference is 3.
How many two digit numbers are divisible by 3?
