Question 1011010

{{{4}}} tests gives an average of {{{60}}}=>the sum of all your grades {{{ 4*60=240}}}
{{{5}}} tests gets you an average of {{{58}}}=>the sum of all your grades  {{{5*58=290}}}

 now subtract the sums, {{{290-240}}}, and you get {{{50}}}

so,his most recent test grade was {{{50}}}

answer is: B. {{{50}}}