Problema Solution
Three friends were comparing the money in their wallets. Alfred and Bob have $65 together. Bob and Charles have $72 together. Alfred and Charles have $79 together. How much money do Alfred, Bob, and Charles have altogether?
Answer provided by our tutors
let
a = the money Alfred has
b = the money Bob has
c = the money Charles has
Alfred and Bob have $65 together:
a + b = 65
Bob and Charles have $72 together:
b + c = 72
Alfred and Charles have $79 together:
a + c = 79
we have the following system of equations:
a + b = 65
b + c = 72
a + c = 79
if we add all the 3 equations together we get:
a +b + b + c + a + c = 65 +72 + 79
2(a + b + c) = 216 divide both sides by 2
a + b + c = $108
Altogether Alfred, Bob, and Charles have $108.