Question 1052885
[ ave mark ] = [ total of marks ] / [ number of students ]
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For all the students:
{{{  61 = T / 35 }}}
{{{ T = 2135 }}}
Total of marks for all students
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For the girls:
{{{ 65 = T/15 }}}
{{{ T = 975 }}}
Total of marks for girls
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{{{ 2135 - 975 = 1160 }}}
and
{{{ 35 - 15 = 20 }}}
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Let {{{ x }}} = the average mark for the boys
{{{ x = 1160/20 }}}
{{{ x = 58 }}}
The average mark for the boys is 58