Please help!

Question

At a cup cake baking competition, Alan baked 55 fewer cupcakes than Tom while Sally baked twice as many cupcakes as what Alan and Tom baked together. If the three of them baked a total of 1125 cupcakes, how many cupcakes did Tom bake?

Many thanks

Answer 1

a = t-55
s = 2(a+t)
a+t+s = 1125

a = 160
t = 215
s = 750

Answer 2

A wooden crate half full pineapples has a mass of 14kg. The same crate one third full of pineapples has a mass of 12kg.
What is the mass of the empty crate?

Please help! Many thanks.