If seven friends eat out and split a bill, we must first figure out how much each person would pay individually. To find this number, we need to divide the total bill by the total number of people. $100. 10/7 = 14.3, so each person payed $14.3 individually. If three friends only brought cash so they pay Henry to pay for their portion on credit card, then Henry would pay for those three friends and himself on a credit card, or just 4 times how much one of them payed. Since each of them payed 14.3, then to find out how much Henry payed on credit card, we need to multiply 14.3 by 4 which gives us our answer of $57. 12