Question

the sum of three consucative numbers in an A.P. is 21 and their product is 231 . find the number

Answer 1

let the three numbers be (a-d) , a , (a+d)

Answer 2

Let the AP is (a-d), a, (a+d)

(a-d)+a+(a+d) =21

3a=21

a=7

(a-d)×a×(a+d)=231

(a×a-d×d) ×a=231

(7×7-d×d)×7=231

(7×7-d×d)=231÷7

(7×7-d×d)=33

d×d=49-33

d×d=16

d=4

Hence, the A. P. is 3, 7, 11.