three numbers are in AP and the sum is 21 find the middle number
Answers
Answered by
1
Let the numbers be a,b, c
b=(a+c/2)
b=(21-b)/2
2b=21-b
3b=21
b=7.
Answered by
0
Answer:
a=7
Step-by-step explanation:
a,a+d,a+2d
21a=3
a=21÷3
a=7
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