Question 758341
During his shift at the school carnival he sold 112 drinks.
 He thought he only needed to keep track of the total amount of drinks
 sold, but it turns out they want to know how many bottles of water
 and how many bottles of soda were sold as separate numbers.
 The question is: If the number of bottles of water sold was 4 less
 than 3 times the number of bottles of soda, how many of each did he sell?
:
Let w = no. of bottles of water sold
Let s = no. of bottles of soda
:
Total sold equation
w + s = 112
w = (112-s); use this for substitution
:
"the number of bottles of water sold was 4 less
 than 3 times the number of bottles of soda,"
w = 3s - 4
A big mistake here. Let me correct this
Replace w with (112-s)
112-s = 3s - 4
112 + 4 = 3s + s
116 = 4s
s = 116/4
s = 29 sodas
then
w = 112 - 29
w = 83 waters sold
:
See if that checks out in the statement:
"the number of bottles of water sold was 4 less
 than 3 times the number of bottles of soda,
83 = 3(29) - 4
83 = 87 - 4