~Before answering any questions I found out how much money does each person has.
~In the question it says that Boris has 2 1/2 times as much as Anna.
~To find this I converted 2 1/2 into a decimal. In the fraction there are 2 wholes, so in the decimal there is a 2 in the ones place or one place to the left from the decimal. Then I converted 1/2 into a decimal by dividing the numerator by the denominator. Which is 0.5. Then I just put the two numbers together which is 2.50.
~To find how much money Boris has is by multiplying 2.50 by Anna's amount of cash which is $25.60. This is because in the question is says that Boris had 2 1/2 TIMES as much as Anna. The product to this question is $64.00.
~Next I found out how much money does Charlie have.
~I converted 3/4 into a decimal by dividing 3 by 4 which is 0.75.
~Then i multiplied 3/4 by 25.60. Then the answer I get is $19.20.
~In this picture I showed how I got my answer.
~I added Anna's, Charlie's and Boris' amount of money to get how much money they had all together.
~Which was $108.80
~ In order to find how much more money does Boris have than Charlie is by subtracting Boris' amount of money by Charlie's amount of money.
~ So the expression is 64 - 19.20 and the difference is $44.80.