Consider that 10 arithmetic means are inserted between 3 and 7 and their sum is "a". Again consider that the sum of five numbers in A.P. is 30 and the value of the middle term is "b". Then a + b equals :
1) 16
2) 56
3) 46
4) 36
Please explain your answer :)
Answers
Answered by
32
Answer:
Option (2) 56
Step-by-step explanation:
Sum of the 10 numbers in AP will be
a = sum of all the 12 numbers in AP - (3 + 7)
= (12/2)(first term + last term) - 10
= 6 × (3 + 7) - 10
= 60 - 10
= 50
Thus, a = 50
If sum of 5 numbers in AP is 30 then let the first of these five numbers be x
using the formula of the sum of an AP
or,
or,
or,
But x + 2d gives the thrd term of the five terms in AP [∵ nthterm of AP is given by a + (n - 1)d]
Therefore the third term = 6
or b = 6
Therefore
a + b = 50 + 6 = 56
Answered by
12
Answer:
Consider that 10 arithmetic means are inserted between 3 and 7 and their sum is "a". Again consider that the sum of five numbers in A.P. is 30 and the value of the middle term is "b". Then a + b equals :
1) 16
2) 56✅
3) 46
4) 36
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