Question 832434
Let {{{ x }}} = the number of problems on the test
{{{ x - 5 }}} is the number answered correctly
{{{ ( x-5 ) / x = .89 }}}
{{{ x - 5 = .89x }}}
{{{ .11x = 5 }}}
{{{ x = 5/.11 }}}
{{{ x = 45.45 }}}
There were 45 problems on the test
check:
The student missed 5, so 40 were answered correctly
{{{ 40/45 = .888 }}}
close enough