Question

Find three numbers in AP whose sum is 21 and whose produce is 315

Answer 1

ANSWER:

Let 3 no.s be (a-d),a,(a+d).

then,

    a-d+a+a+d = 21

or, 3a = 21

or, a = 7

now,  

     (a-d)(a+d)a = 315

or, (a^2 - d^2)7 = 315

or,  (a^2 - d^2) = 45

or, 7^2 - d^2 = 45

or, 49 - d^2 =45

or, d^2 = 49 - 45

or, d = root over of 4

or, d = 2

The 3 no.s are 5 , 7 , 9..

Answer 2

Answer:

the answer will be 5,7,9