Answer:
68
Explanation:
Find the vanilla first by dividing 420 by 7 and multiplying the quotient by 2 to get 120.
Then find the banana using the equation 35/100 = x/420, cross multiply to get 147.
Add 120 and 147 to get 267.
Subtract 267 from 420 to get 153.
Divide 153 by 9 to get 17.
Get the number of lemon cakes by multiplying 17 by 4.
The number of lemon cakes is 68!
(and chocolate cakes is 85)