What difficulty are you having? Do you understand that this is justarithmetic? You know how to multiply by 2, dont you? The first week would be 2 cents, the second week, 4 cents, the third week 8 cents, the fourth week 16 cents, the fifth week 32 cents.... You can continue just multiplying by two but the problem will be simpler if you recognise those numbers as "powers of 2": , , , , .... Get the idea?