Question

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

Answer 1

1/5 = 20% so 50+20=70
100-70=30
so 30%

Answer 2

Answer: 30% of the cakes were sponge cakes.

Step-by-step explanation: We are given that 50% of the cakes Jenny baked that week were party cakes, one-fifth were fruit cakes and the remainder were sponge cakes.

We are to find the percentage of cakes that were sponge cakes.

Let n represents the number of cakes that Jenny baked.

According to the given information, we have

`C_p=50\%* n=(50)/(100)* n=(n)/(2),\\\\\\C_f=(1)/(5)* n=(n)/(5).`

Therefore, the number of sponge cakes is given by

`C_s=n-C_p-C_f=n-(n)/(2)-(n)/(5)=(10-5n-2n)/(10)=(3n)/(10).`

Therefore, the percentage of cakes that were sponge cakes is given by

`C_s\%=((3n)/(10))/(n)*100\%=30\%.`

Thus, 30% of the cakes were sponge cakes.