# Tutor.com Linear Equations Session

##### Mar. 5, 2012

Session Transcript - Math - Algebra, 3/1/2012 1:28PM - Tutor.comSession Date: 3/1/2012 1:28PM
Length: 27.4 minute(s)
Subject: Math - Algebra

System Message
[00:00:00] *** Please note: All sessions are recorded for quality control. ***

Guest (Customer)
[00:00:04] A store sells adult t shirts for 14.99 and child t shirts for 11.99. In one day they took in a total of 278.79 from selling 21 t shirts. How many of each t shirt did they sell?

Champika W (Tutor)
[00:00:10] Welcome to Tutor.com ! Let's get started.
[00:00:12] :)
[00:00:29] hello

Guest (Customer)
[00:00:42] hey girl!

Champika W (Tutor)
[00:01:02] :)
[00:01:39] have you started on the problem or do you need help getting started?

Guest (Customer)
[00:02:09] I need help coming up with the equation.

Champika W (Tutor)
[00:02:19] alright..
[00:03:03] let's say the number of adult T shirts = A and number of child Tshirts = C
[00:03:31] then we can two equations from the given information
[00:03:43] which has variables A and C
[00:03:55] are you with me upto now?

Guest (Customer)
[00:04:04] Yes..

Champika W (Tutor)
[00:04:14] ok..
[00:04:36] so the question says total number of Tshirts sold is 21
[00:04:59] we know the number of adult shirts = A and number of child Tshirts = C
[00:05:12] can you write an equation relating those?

Guest (Customer)
[00:05:32] yes. a+c=21

Champika W (Tutor)
[00:05:38] very good!
[00:05:46] that's our first equation
[00:05:55] let's form the second
[00:06:03] it's about the cost
[00:06:22] we know that the total cost is 278.79
[00:06:45] and an adult T shirt cost 14.99 and child Tshirt cost 11.99
[00:06:58] can you form and equation with that info?

Guest (Customer)
[00:07:37] 14.99 (a) + 11.99 (c) =278.79

Champika W (Tutor)
[00:07:46] excellent!
[00:07:47] :)
[00:08:03] now the rest is a matter of solving two linear equations
[00:08:15] do you know how to do that?

Guest (Customer)
[00:08:25] No that seems to be the problem..

Champika W (Tutor)
[00:09:09] alright.. from first equation you can isolate either A or C and substitute that in the second equation
[00:09:18] does that make sense?

Guest (Customer)
[00:09:53] do you mean a=21-c

Champika W (Tutor)
[00:10:00] yes..
[00:10:34] so in the second equation you can write (21-C) instead of A
[00:10:48] then you will have an equation with just C and numbers
[00:10:57] you can find C from there
[00:11:11] then plug it back to first equation to find A
[00:11:26] does that make sense?

Guest (Customer)
[00:12:31] 14.99 (21-c)+11.99 (c)=278.79 but I'm not sure how to solve it

Champika W (Tutor)
[00:12:54] it is correct..
[00:13:18] first multiply the bracket by 14.99
[00:13:31] then add/subtract the like terms
[00:13:43] and find c
[00:14:36] did you understand that?

Guest (Customer)
[00:15:14] is the answer 12 for c?

Champika W (Tutor)
[00:15:22] yes..

Guest (Customer)
[00:15:45] okay thank you! can i ask you one more question?

Champika W (Tutor)
[00:15:51] sure
[00:16:09] dont forget you have to find A also

Guest (Customer)
[00:16:47] after a 12% price reduction a coat sold for \$176. what is the coats price before reduction?

Champika W (Tutor)
[00:18:10] If reduction was 12%, what was the percent of the original price the coat was sold?
[00:18:50] did you understand my question?

Guest (Customer)
[00:18:58] no..

Champika W (Tutor)
[00:19:57] ok..so 12% was the price reduction. Then we can say the coat was sold for (100-12)% of it's original price
[00:20:16] does that make sense?

Guest (Customer)
[00:20:22] yes

Champika W (Tutor)
[00:20:44] so the coat was sold for 88% of it's original price
[00:21:22] do you know how to find the original value then?
[00:21:44] we know 88% of original proice is \$176

Guest (Customer)
[00:22:07] do you multiply?

Champika W (Tutor)
[00:22:40] mm.. no. if we multiply we will get a number less than \$176
[00:22:48] 88% is same as 88/100
[00:23:02] let's call the original value x
[00:23:22] if 88/100 of x is 176, what is x?
[00:24:25] that is the equation form
[00:24:29] is it clear?

Guest (Customer)
[00:24:51] yes sorry i got a little flustered

Champika W (Tutor)
[00:24:58] no worries..
[00:25:12] did you understand the concept now?

Guest (Customer)
[00:25:48] is the answer 200?

Champika W (Tutor)
[00:25:55] yes
[00:26:01] Do you have any questions about anything we went over today?

Guest (Customer)
[00:26:48] No I think I understand. Thank you so much for all your help, I'm sure I will be back!

Champika W (Tutor)
[00:26:58] :)
[00:27:01] you are welcome
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[00:27:10] have a great day!