Problem 1:

A total of 16 people attending Hannah's party. Including 14 friends, Hannah and her mother.

a) The number packets of cake do they need to buy for the party is:

 16 : ( 6 : 3 ) = 8 ( packets )

b) The number packets of sweets they need to buy for the party is:

15 : 5 = 3 ( packets )

c) They need to pay that amount is :

( 2,99 x 8 ) + ( 2,89 x 3 ) = 32,59 ( ₤ )

d) Hannah's mother's remaining money is:

( 20 x 2 ) - 32,59 = 7,41 ( ₤ )

The end : a) 8 packets   b) 3 packets   c) 32,59₤   d) 7,41₤

Problem 2:

a) The number packs of pencils he need to buy is:

( 34 x 2 ) : 6 = 11 ( packs ) (residual : 2 ea )

b) He need to pay that amount is:

(1,99 x 11 ) + (( 1,99 : 6 ) x 2 ) = 24,55 ( ₤ )

He's remaining money is:

30 - 24,55 = 5,45 ( ₤ )

The end : a) He need to buy :11  packs, but residual : 2 ea

                b) He pays:  24,55 ( ₤ )   end He's remaining : 5,45 ( ₤ )