If jane give £2 pounds to charlotte they will have equal amount of money. instead charlotte give £4 to jane the ratio of jane's money to charlotte will be 2:1. how much
do jane and charlotte each have to start with​

Jane has 20 pounds and Charlotte has 16 pounds

Let j = amount Jane has and c = amount Charlotte has

j - 2 = c + 2 if Jane gives Charlotte 2 pounds
j + 4 = 2(c - 4) if Charlotte gives Jane 4 pounds
j + 4 = 2c - 8
Subtract equation 1 from equation 3
6 = c - 10
c = 16
j = c + 4 = 20