I am trying to solve a simple puzzle:
Fifty Minutes ago if it was four times as many minutes past three O'clock, how many minutes is it to six O'clock.
I tried solving it:
Let x be the minutes past 5, then 120 + x - 50 = 4x
which gives the wrong answer.
The correct solution has the formulation 180 - 50 -x = 4x which gives x = 26 and is the correct answer.
Am I doing weird thing by assuming that x is the minutes past 5 ? My approach is same as the one with correct solution if I use 4(60 -x) on the LHS but why should I ?
Is it that the puzzle is wrong in its formulation or am I missing something and hence am unable to arrive at the correct solution ?
By the way, the puzzle is from a famous book by Shakuntala Devi and hence I am forced to doubt the validity of my approach.