find v

[poonamchiK]

For all real nos. v, the operation v*= v-v.
3
If (V*)*=8 then v = ?
a.15
b. 18
c. 21
d. 24
e. 27

thx in advance

[ps63739]

V* = V - V.3?

That way it comes out to be 2, which is not the answer?

[poonamchiK]

sorry question is :
For all real nos. v, the operation v*= v-v/3

If (V*)*=8 then v = ?
a.15
b. 18
c. 21
d. 24
e. 27

thx in advance. answer = b

[Ben Ku]

Please cite the source (author) of this problem. We cannot reply unless a source is cited (and, if no source is cited, we will have to delete the post!). Thanks.

[thoppae.saravanan]

I guess picking up the numbers from the options will be the easiest way to solve this problem. Picking up option B satisfies the equation and gives the right answer.