Question 936919
1.

if all  give contributions each one will be giving {{{(1/15)}}} of {{{C}}}, or {{{C/15}}}

so, answer is: B. {{{C/15}}}

2.

there is {{{x}}} students
If "{{{3/5}}} of the students are dismissed at {{{3:30p.m}}}", we have {{{(3/5)x}}} dismissed

{{{x-(3/5)x }}} will be {{{reminder}}}

and if {{{3/4}}} of the {{{remainder}}} dismissed at {{{4:00p.m.}}},we have : 

{{{(3/4)(x-(3/5)x)}}}

={{{(3/4)(5x/5-3x/5)}}}

={{{(3/4)(2x/5)}}}

={{{6x/20}}}

={{{3x/10}}}  are dismissed  at 4:00 p.m

all together:

{{{(3/5)x+3x/10}}}   are dismissed  which is {{{(6/10)x+3x/10=9x/10}}}

so,we can write {{{x}}} as {{{x=10x/10}}}, then we have {{{10x/10-9x/10=(1/10)x}}}=> means {{{1/10}}} of the students are dismissed at other times

and your answer is: B. {{{1/10}}}