Advertisements
Advertisements
Question
Choose the correct alternative answer for the following question .
If for any A.P. d = 5 then t18 – t13 = ....
Options
5
20
25
30
Advertisements
Solution
It is given that,
d = 5
Now,
\[t_n = a + \left( n - 1 \right)d\]
\[ t_{18} - t_{13} = \left( a + \left( 18 - 1 \right)d \right) - \left( a + \left( 13 - 1 \right)d \right)\]
\[ = \left( a + 17d \right) - \left( a + 12d \right)\]
\[ = 5d\]
\[ = 5\left( 5 \right)\]
\[ = 25\]
APPEARS IN
RELATED QUESTIONS
Find the sum of the following APs:
2, 7, 12, ..., to 10 terms.
Which term of the progression 20, 19`1/4`,18`1/2`,17`3/4`, ... is the first negative term?
Find the sum of the following arithmetic progressions:
41, 36, 31, ... to 12 terms
Find the sum of the following arithmetic progressions:
−26, −24, −22, …. to 36 terms
Find the sum of the first 25 terms of an A.P. whose nth term is given by an = 7 − 3n
Find the sum of all odd natural numbers less than 50.
If the sum of first m terms of an AP is ( 2m2 + 3m) then what is its second term?
Find the sum of first n even natural numbers.
Two A.P.’s are given 9, 7, 5, ... and 24, 21, 18, ... If nth term of both the progressions are equal then find the value of n and nth term.
If m times the mth term of an A.P. is eqaul to n times nth term then show that the (m + n)th term of the A.P. is zero.
Fill up the boxes and find out the number of terms in the A.P.
1,3,5,....,149 .
Here a = 1 , d =b`[ ], t_n = 149`
tn = a + (n-1) d
∴ 149 =`[ ] ∴149 = 2n - [ ]`
∴ n =`[ ]`
If the 10th term of an A.P. is 21 and the sum of its first 10 terms is 120, find its nth term.
The sum of first n terms of an A.P. is 3n2 + 4n. Find the 25th term of this A.P.
Write 5th term from the end of the A.P. 3, 5, 7, 9, ..., 201.
For what value of p are 2p + 1, 13, 5p − 3 are three consecutive terms of an A.P.?
If the sums of n terms of two arithmetic progressions are in the ratio \[\frac{3n + 5}{5n - 7}\] , then their nth terms are in the ratio
The sum of the first three numbers in an Arithmetic Progression is 18. If the product of the first and the third term is 5 times the common difference, find the three numbers.
Find the sum of three-digit natural numbers, which are divisible by 4
Jaspal Singh repays his total loan of Rs. 118000 by paying every month starting with the first instalment of Rs. 1000. If he increases the instalment by Rs. 100 every month, what amount will be paid by him in the 30th instalment? What amount of loan does he still have to pay after the 30th instalment?
Find the sum of first 20 terms of an A.P. whose nth term is given as an = 5 – 2n.
