I am just learning variable expressions. My homework is to write a variable expression for each word phrase;
example :
the number of minutes in s seconds
the cost of x cartons of juice at $.75 each
And etc.
I don't understand it
Thank you
Brittany
8th grader
Hi Brittany,
Sometimes it helps to try some numbers for the variable. Let's do the second example first.
Numeric value for x 
Cost of x cartons of juice 
1  $0.75 
2  $1.50 
3  $2.25 
4  $3.00 
That is one carton of juice costs $0.75
Two cartons of juice cost $0.75 + $0.75 = 2($0.75) = $1.50
Three cartons of juice cost $0.75 + $0.75 + $0.75 = 3($0.75) = $2.25
Each time you multiply $0.75 by the value for x, in other words, x($0.75). Thus
the cost of x cartons of juice at $0.75 each is x($0.75)
For the first problem, what values if s make the calculation easy?
If s is 60 seconds then the nunber of minutes is 1.
If s is 120 seconds then the nunber of minutes is 2.
If s is 180 seconds then the nunber of minutes is 3.
If s is 90 seconds then the nunber of minutes is 1 ^{1}/_{2}.
This time what you are doing is dividing the number if seconds by 60. Thus
the number of minutes in s seconds is ^{s}/_{60}
Now try the rest of the problems.
Penny
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