Sabrina ordered some cupcakes for a party. 1/3 of the cupcakes were
lemon-flavoured, 3/8 were vanilla and 5/7 of the remaining cupcakes were
strawberry-flavoured. The rest were chocolate cupcakes. There were 60
more lemon-flavoured cupcakes than strawberry-flavoured cupcakes.
(a) What fraction of the cupcakes were chocolate?
(b) How many cupcakes did Sabrina order?