Advertisements
Advertisements
Question
If the terms 10, a, 40 are in A.P., then find the value of a.
Options
35
20
25
30
Solution
25
Explanation:
The terms 10, a, 40 are in A.P.
Then t2 – t1 = t3 – t2
So, 40 – a = a – 10
⇒ 40 + 10 = a + a
⇒ 2a = 50
⇒ a = 25
Thus, the value of a is 25.
APPEARS IN
RELATED QUESTIONS
The 13th term of an A.P. is four times its 3rd term. If its 5th term is 16, then find the sum of its first ten terms.
Find the middle term of the A.P. 213, 205, 197, ---, 37.
Four numbers are in A.P. If their sum is 20 and the sum of their square is 120, then find the middle terms
For the following A.Ps, write the first term and the common difference.
0.6, 1.7, 2.8, 3.9
Following are APs or not? If they form an A.P. find the common difference d and write three more terms:
1, 3, 9, 27 …
For the following arithmetic progressions write the first term a and the common difference d:
−1.1, −3.1, −5.1, −7.1, ...
Find 8th term of the A.P. 117, 104, 91, 78, ...
Write the expression an- ak for the A.P. a, a + d, a + 2d, ... Hence, find the common difference of the A.P. for which
20th term is 10 more than the 18th term.
Show that (a − b)2, (a2 + b2) and (a + b)2 are in A.P.
Which of the following sequences is arithmetic progressions. For is arithmetic progression, find out the common difference.
12, 52, 72, 73, ...
How many three digit numbers are divisible by 7?
Find x, y and z, given that the numbers x, 10, y, 24, z are in A.P.
Choose the correct alternative answer for the following sub question.
In an Arithmetic Progression 2, 4, 6, 8, ... the common difference d is ______
Find d if t9 = 23 व a = 7
In an AP, if d = -2, n = 5 and an = 0, the value of a is ______.
Find a, b and c such that the following numbers are in AP: a, 7, b, 23, c.
Split 207 into three parts such that these are in AP and the product of the two smaller parts is 4623.
In which of the following situations, do the lists of numbers involved form an AP? Give reasons for your answers.
The number of bacteria in a certain food item after each second, when they double in every second.
Verify that the following is an AP, and then write its next three terms.
a, 2a + 1, 3a + 2, 4a + 3,...
First term and common difference of an A.P. are 1 and 2 respectively; find S10.
Given: a = 1, d = 2
find S10 = ?
Sn = `n/2 [2a + (n - 1) square]`
S10 = `10/2 [2 xx 1 + (10 - 1)square]`
= `10/2[2 + 9 xx square]`
= `10/2 [2 + square]`
= `10/2 xx square = square`
