Problem
First name
Sarah
School
St Mary's Amersham
Country
Age
11
Imagine Alison deposits £2, another £2, another £2, another £2 and then finally withdraws £3. She now has an extra £5 in her account.
What other amounts of money is it possible for Alison to change her account balance by? £1, £3, £7, £9, £11 etc… if you only withdraw 1 lot of £3 it equals odd numbers but if you withdraw 2 lots of £3 it equals the even numbers
Charlie's Bank wants to change its rules whilst ensuring that its customers can still change their account balance by any total.
If Alison is only allowed to deposit £3 at a time and withdraw £7 at a time, will she be able change her account balance by any total? Yes: £3+£3+£3=£9. £9-£7=£2.