Average rate of change implies the quotient f(4)-f(a)/4-a which equals (1/2-a/2)/4-a=(1-a)/(8-2a) on (4,a)
It would be 25 how I got that answer was I did 200 ÷ 8 and that gave me 25
50% is equal to 5/10 so 5/10 were party cakes 1/5x2=2/10 so 2/10 were fruit cakes 5/10+2/10=7/10 so 10/10 which is 100% of all cakes 10/10-7/10=3/10 so 3/10 of the cakes were sponge cakes.
Commutative i believe <span />
