207k views
3 votes
if the cost of 3 chocolates and 2 cookies is $22 and that of 2 chocolates and 3 cookies is $18, what is the cost of cookies.​

User Pankajt
by
7.9k points

2 Answers

4 votes

Answer:$2

Step-by-step explanation:Express as two equations . Lex x Be chocolate and y be cookies.

3x+2y=22

2x+3y= 18

Common factor of 6 so times first ran by 2, second ran by 3 . Eliminate.

User Alfredo
by
7.7k points
3 votes

Answer:

$2

Explanation:

Let the cost of a chocolate and a cookie be $x and $y respectively.

Using the given information, form 2 equations and label them.

3x +2y= 22 -----(1)

2x +3y= 18 -----(2)

Now let's try to multiply both equations by a certain integer, such that the coefficient of x in both equations are the same. This allows us to eliminate the x term through subtraction.

(1) ×2:

6x +4y= 44 -----(3)

(2) ×3:

6x +9y= 54 -----(4)

(4) -(3):

6x +9y -(6x +4y)= 54 -44

Expand, simplify:

6x +9y -6x -4y= 10

5y= 10

Dividing both sides by 5:

y= 10 ÷5

y= 2

Thus, a cookie costs $2.

Note:

• Since we are only trying to find the value of y (cost of cookie), it is faster to eliminate the x term.

• If the signs of the coefficient of the term is opposite (e.g. -6 and 6), we can eliminate the term through addition.

Example:

-6x +4y= 44 -----(1)

6x +9y= 54 -----(2)

(1) +(2):

-6x +4y +6x +9y= 44 +54

13y= 98

y= 98 ÷13

y= 7.54 (3 s.f.)

User Peter Kneale
by
8.6k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories