Question

50% of all the cakes Jenny baked that week were party cakes 1/5 were fruit cakes, what presentage of cakes were sponge cakes

Answer 1

1 divided by 5 = 0.2
0.2 is 20%
So 20% were fruit cakes.

50+20=70 and
100-70=30.

Assuming there were no other type of cakes that jenny baked, 30% were sponge cakes.