<PRE><B>Question 1144751</B>
7/10 of pupils like badmitton, that leaves 3/10 to be divided up
:
3/10 * 5/6 = 15/60 = 1/4, 1/4 like soccer
:
3/10 - 1/4 = 6/20 - 5/20 = 1/20, (1/20)/2 = 1/40, 1/40 like basketball and 1/40 like volleyball
:
7/10 like badminton, 1/4 like soccer, 1/40 like basketball, 1/40 like volleyball
:
Note that 7/10 + 1/4 + 1/40 + 1/40 = 28/40 + 10/40 + 1/40 + 1/40 = 40/40 = 1
:
a.  1/40
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b.  520 * 1/40 = 13 pupils like basketball
:
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