Advertisements
Advertisements
प्रश्न
In an A.P., the first term is 12 and the common difference is 6. If the last term of the A.P. is 252, then find its middle term.
उत्तर
Given, First term, a = 12
Common difference, d = 6
Last term, an = 252
Since, an = a + (n – 1)d
⇒ 252 = 12 + (n – 1) 6
⇒ `240/6` = n – 1
⇒ n = 41
Middle term = `(n + 1)/2`
= `(41 + 1)/2`
= 21st term
Now, a21 = a + (21 – 1)d
= 12 + 20 × 6
= 12 + 120
= 132
Hence, middle term is 132.
APPEARS IN
संबंधित प्रश्न
In the following APs find the missing term in the box:
`square, 13, square, 3`
Subba Rao started work in 1995 at an annual salary of Rs 5000 and received an increment of Rs 200 each year. In which year did his income reach Rs 7000?
Find the indicated terms in each of the following sequences whose nth terms are:
`a_n = (3n - 2)/(4n + 5)`; `a_7 and a_8`
Which term of the A.P. 21, 42, 63, 84, ... is 420?
Find the 12th term from the end of the following arithmetic progressions:
3, 8, 13, ..., 253
How many terms are there in the AP 6,1 0, 14, 18, ….., 174?
If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term will be ______.
The 4th term from the end of the AP: –11, –8, –5, ..., 49 is ______.
Justify whether it is true to say that the following are the nth terms of an AP.
1 + n + n2
Determine the 36th term of the A.P. whose first two terms are –3 and 4 respectively.
