find the 12th term of the ap with sum of its 12 terms is 75 and 11 terms is 62
Answers
Brainly.in
What is your question?
Primary SchoolMath 13 points
If 12th term of an A.P is -13 &the sum of its first 4 terms is 24 what is the sum of its first 10 terms?
Ask for details Follow Report by Hemalatha74 09.05.2018
Answers
Rabia1156
Rabia1156 Helping Hand
The sum of the first 10 terms of the ap is 0
1.5
2 votes
Comments Report
Panzer786
Panzer786 Genius
Hii friend,
12th term of an AP = -13
a+11d = -13......(1)
And,
Sum of first fourth term = 24
N/2× [ 2A + (N-1) × D)] = 24
4/2× [ 2A + (4-1) × D] = 24
2 ×(2A + 3D) = 24
4A+ 6D = 24......(2)
From equation (1) we get,
A + 11D = -13
A = -13-11D......(3)
Putting the value of A in equation (2)
4A + 6D = 24
4 × (-13-11D)+ 6D = 24
-52 - 44D +6D = 24
-38D = 24+52
D = 76/-38 = -2
Putting the value of D in equation (3)
A = -13-11D => -13 - 11 × -2 => -13 +22 => 9
First term (A) = 9
Therefore,
Sum of first 10th term = N/2 × [2A + (N-1) × D]
S10 = 10/2 ×[ 2 × 9 + (10-1) × -2)]
=> 5 ×(18 -18)
=> 0
HOPE IT WILL HELP YOU..... :
Answer:
Step-by-step explanation:
12th term of an AP = -13
a+11d = -13......(1)
And,
Sum of first fourth term = 24
N/2× [ 2A + (N-1) × D)] = 24
4/2× [ 2A + (4-1) × D] = 24
2 ×(2A + 3D) = 24
4A+ 6D = 24......(2)
From equation (1) we get,
A + 11D = -13
A = -13-11D......(3)
Putting the value of A in equation (2)
4A + 6D = 24
4 × (-13-11D)+ 6D = 24
-52 - 44D +6D = 24
-38D = 24+52
D = 76/-38 = -2
Putting the value of D in equation (3)
A = -13-11D => -13 - 11 × -2 => -13 +22 => 9
First term (A) = 9
Therefore,
Sum of first 10th term = N/2 × [2A + (N-1) × D]
S10 = 10/2 ×[ 2 × 9 + (10-1) × -2)]
=> 5 ×(18 -18)
=> 0