Seven friends eat out and decide to split the bill. Three friends only brought cash so they pay Henry who in turn pays for their portion on his credit card. If the total bill amounted to $100.10, then what amount did Henry pay by credit card?

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