<PRE><B>Question 1054030</B>
15 boys take 1 hr to assemble 30 machines
--------------------------------------
15/30 boys take 1 hr to assemble 30/30 machines
1/2 boy take 1 hr to assemble 1 machine
----------------------------------------------
1 boy takes 1 hr to assemble 2 machines
48 boys take 1 hr to assemble 96 machines
------------------------------------------
Note that 40 min = 2/3 hr
48 boys take 2/3 hr to assemble (2/3)*96 machines
48 boys take 40 min to assemble 64 machines
</PRE>