A)
The sponge & Pandan : chiffon is 14:9.
1/3 of chiffon is sold means 3 units are sold away.
The ratio of sponge & Pandan : chiffon become 14:6.
In order to make it comparable to the chiffon : sponge ratio of 4:5, double both sides of 14:6 to make is 28:12.
When tripled both sides for chiffon : sponge, it will be 12:15 and the chiffon will have the same units.
Then, take the units of sponge & Pandan and minus away the sponge units to find the Pandan units.
Lastly, take all the units you have for each type of cake and put them together in a ratio.

With the ratio from part A, we add up all the units to find that there are 40 units and it stands for 680 cakes.
Since the question is only asking for sponge cakes, we will narrow in to the sponge cake which is 15 units.
Giving away 40% will mean being left with 60% which is what the question is asking.
Therefore, just find out how many is 60% of the sponge cakes and you have your answer.