There are four numbers of which the first three are in GP whose commo...
Let the 1st 3 terms be a-d,a,a+d
Ac. to Q. a-d+ a+d=2
Therefore, a=1
Now, let the last 3 terms be a,ar,ar2
Ac. to Q. a+ar2= 26
a(1+r2)=26
r2 =25
Therefore, r= +5 and -5
Therefore, the no.'s are -3,1,5,25 or 7,1,-5,25
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There are four numbers of which the first three are in GP whose commo...
Given Information:
- The first three numbers are in geometric progression (GP) with a common ratio of 1/2.
- The last three numbers are in arithmetic progression (AP).
- The last number is 2 less than the first number.
Let's solve this problem step by step:
Step 1: Understanding Geometric Progression (GP)
- In a geometric progression, each term is obtained by multiplying the previous term by a constant called the common ratio.
- The general form of a geometric progression is: a, ar, ar^2, ar^3, ...
where 'a' is the first term and 'r' is the common ratio.
Step 2: Finding the First Three Numbers
- Let the first number be 'a'.
- The second number would be 'ar' (since it is in GP).
- The third number would be 'ar^2' (since it is in GP).
Step 3: Understanding Arithmetic Progression (AP)
- In an arithmetic progression, each term is obtained by adding a constant called the common difference to the previous term.
- The general form of an arithmetic progression is: a, a+d, a+2d, a+3d, ...
where 'a' is the first term and 'd' is the common difference.
Step 4: Finding the Common Difference
- Since the last three numbers are in AP, the common difference would be 'd'.
- The last number would be 'a+2d' (since it is 2 less than the first number).
Step 5: Equating the Last Numbers
- Since the last number is 2 less than the first number, we can equate the expressions for the last number obtained in Steps 3 and 4.
(a+2d) = (a-2)
Step 6: Solving for 'a' and 'd'
- Solving the equation from Step 5, we get: a = 2d-2
Step 7: Finding the First Three Numbers (Continued)
- Substituting the value of 'a' from Step 6, we get: a = 2(2d)-2
Simplifying, we get: a = 4d-2
- The first three numbers are therefore: (4d-2), (2d-2), (2d-2)(1/2)
Step 8: Finding the Fourth Number
- The fourth number is obtained by adding the common difference to the third number, which is (2d-2)(1/2).
- The fourth number would be: [(2d-2)(1/2)] + d
Step 9: Equating the Fourth Number with the First Number
- Since the fourth number is equal to the first number, we can equate the expressions obtained in Steps 7 and 8.
(4d-2) = [(2d-2)(1/2)] + d
Step 10: Solving for 'd'
- Solving the equation from Step 9, we get: d = 6
Step 11: Finding the First Four Numbers
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