50 out of the 80 were adults if you have to round so it would be 5/8 then you just do 8×100 and then 5×180+70÷100 because you're want to do not do not do it
Answer:
By definition, the derivative of f(x) is

Let's use the definition for 

Then, 
It would be 60. He sold his painting for 50 which was 10 less that the original price. So 50+10=60
We have the area of the base of a triangular prism= a*b
the volume of triangular prism =a*b*c( where c is the height) so that 210=a*b*14 ==> 210= base area*14==> base area= 210/14