Answer:
The battery cost = £0.43
Explanation:
Tim buys a torch and a battery . The torch cost 11 times as much as the battery.
let
cost of battery = a
cost of torch = 11a
The amount he paid is £10 note and he got a change of £4.86. That means he bought both items for 10 - 4.86 = £5.14 .
total cost = a + 11a
5.14 = a + 11a
5.14 = 12a
divide both sides by 12
a = 5.14/12
a = 0.42833333333
a = 0.428
a ≈ 0.43
The battery cost = £0.43