Question 350617
For A:
{{{A/10=80}}}
{{{A=800}}}
.
.
.
For B:
{{{B/20=90}}}
{{{B=1800}}}
.
.
.
So the average for both combined would be 
{{{Avg=(A+B)/(10+20)=(800+1800)/(10+20)=2600/30=highlight(86.67)}}}