Answer:
the answer is in the attachment
We know that
<span>An electrician can wire a house in ------------> 20 hours
so
100%----------------> 20 hours
X-------------------> 12 hour
x=12*100/20----> x=60%
that means
</span><span>the apprentice in 12 hours complete the (100-60)----> 40%
</span>the apprentice in 12 hours complete -------> 40%
x hours------------------------------------> 100%
x=100*12/40-----> x=30 hours
the answer is
30 hours
False. they could be skew
..................
..
.....
It depends on what did you mean by saying perfect square. If I've understood it correctly, I can help you with a part of your problem. The squares of mod <span>9</span><span> are </span><span><span>1</span><span>,4,7</span></span><span> which are came from </span><span><span>1,2,</span><span>4.</span></span><span> </span>Addition of the given numbers are 2,3,5,6, 8, which are exactly the part of your problem. This number, which is not shown as squares Mod 9, and thus doesn't appear as a sum of digits of a perfect square. I hope you will find it helpful.
