2/3 of Strawberry and 2/3 of Chocolate sold would also mean 2/3 of the total sold. Since 2/3 is the common factor.

So left over would be 1/3 of Strawberry and 1/3 of Chocolate, which again imply 1/3 of total since 1/3 is the common factor.

a) Cupcakes left = 1/3 X 1800 = 600 ###

b) She made another 55 strawberry and 95 chocolates, that is an additional 150 cupcakes. This brings your leftover cupakes to 750 cupcakes

If strawberry is now 1/2 of chocolate, that means strawberry is 1 unit and chocolate is 2 units, which mades 3 units for the total.

3 units =750
1 unit = 750/3 = 250 => strawberry

Now we trace back the strawberry to the morning.
before she baked the 55 strawberry = 250 – 55 = 195
195 is 1/3 of morning strawberry.
Therefore in the morning she bakes = 195 X 3 = 585 strawberry cupcakes. ####