Question 950221


{{{4x + 3(30-x) = 100}}}
{{{4x + 90 -3x = 100}}}
{{{4x = 100-90}}}
{{{x = 10}}}

Answer: there is {{{10}}} problems have {{{4}}} points 
Proof:
=> {{{4*10 + 3*20}}}
=> {{{40  + 60}}} points
=>{{{ 100}}} points