.
of the number of labour cards issued to some artisans by obuasi labour office,
1/3 were issued to carpenters,
1/3 of what remained to drivers,
1/4 of what still remained to masons and the remainder, being 15 to welders.
how many masons were issued with labour cards by the office?
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It is a joke Math problem to be solved in one sentence in two lines.
+--------------------------------------------------------------------------+
| Notice that the number of mason cards was one third |
| of the number of the welder cards, i.e. 1/3 of 15, so the answer is 5. |
+--------------------------------------------------------------------------+
ANSWER. 5 mason cards were issued.
Solved. At this point, the solution is complete.
------------------
To solve such problems successfully, two conditions are necessary and sufficient:
(1) You should read the problem attentively,
probably, several times, if needed,
and
(2) Your mind should be turned on.
////////////////////////
The problems of this kind may have several purposes.
One purpose is obvious: to entertain and to make you laugh,
when you will get an idea of solution.
The other purpose is to teach a reader to make a jump
in his/her mind and to think out of a box.
Third purpose is to give such a problem at an interview to check
if a person is able to think out a box.
What is NOT a purpose of this problem, is to teach solving it
via equations. Had this problem be targeted on using equations,
it would be posed by another way.
And now let me tell you THIS: if at the interview a person will solve
this problem using equations, as the other tutor did in his post,
then, regardless of the fact that his/her solution might be correct, the final
conclusion of the interviewers will be that the person can not think out a box.
Joke Math problems are a special class of Math problems. They combine
Math skills with humor, sometimes in hidden form.
Similar to other Math problems, joke Math problems are also
a subject to teach and a subject to learn.
As I work at this forum just for many years, I did not observe any single case
when visitors or tutors did really react and recognize joke Math problems adequately.
It looks like for many at this forum, joke Math problems are "terra incognita".
of the number of labour cards issued to some artisans by obuasi labour office, 1/3 were issued to carpenters, 1/3 of what remained to drivers, 1/4 of what still remained to masons and the reminder, being 15 to welders. how many masons were issued with labour cards by the office?
of what STILL remained, was issued to masons, so of what STILL remained was
issued to welders. This so happens to be 15 cards. With M being the amount issued to masons,
we get the following PROPORTION:
3M = 15 ----- Cross-multiplying
Number of cards issued to masons, or