Question 1035721
i will use elimination method
{{{c+i=120}}} multiply by 1
{{{c-(i/4)=90}}} multiply by 4
.
{{{c+i=120}}} 
{{{4c-i=360}}} add equations together
{{{5c=480}}} divide by 5
{{{c=96}}}

96 correct 24 incorrect (24/4=6)
96 marks minus 6 marks =90 marks