DAY 05

Comment

An extra small button costs an extra 8p.

Answer

A large button costs 11p.

Readers' methods

Casey, of Barnstaple Road, Taunton:
One small button costs 54p - 46p = 8p.
So 2L + 24 = 46
so 2L = 22,
so L = 11.

Susanne G, Munich, Germany
We have
I. 2x + 3y = 46
and
II. 2x + 4y = 54
from II. you get
2x = 54 - 4y
then put II. into I.
54 - 4y + 3y = 46
then 54 - 46 = y
so y = 8.
Put y into II.
2x = 54 - 4*8
so 2x = 54 - 32
so 2x = 22
so x = 11
so a large button costs 11p and a small one 8p.