Explanation:
carly had nothing, amount of money = £0
amy gave her £7 and brad gave her £5,
carly now has £5 and £7
amount of money of carly= £7 + £5
= £12
you are told that they all have the same amount of money and you know that carly has £12. so:
amy has £12, brad has £12 too.
If amy has £ 12 now after giving away £7, then: let x be the initial amount of money amy had,
x - 7 = 12
x = 12 + 7
x = 19
thus, amy had £19.
have a beautiful day/night!
-s.