Ahmed spent 1/3 of his money on a burrito and a water bottle. the burrito cost 2 times as much as the water. the burrito cost $4. how much money does ahmed have left?

Ahmed's left with $12

Step-by-step explanation:

step 1

Find out the cost of a water bottle

Let

x -----> the cost of a water bottle

y ----> the cost of the burrito

-----> equation A

-----> equation B

substitute equation B in equation A and solve for x

therefore

The cost of a water bottle is $2

step 2

Find out how much money does Ahmed have left

Let

x -----> the amount of money Ahmed originally had

we know that

The cost of a burrito and a water bottle is equal to one third of the amount of money Ahmed originally had

so

Solve for x

Multiply by 3 both sides

therefore

The amount of money Ahmed originally had was $18

If he spent 1/3 of his money

then

He's had 2/3 of the money left.

Multiply 2/3 by the amount of money Ahmed originally had

therefore

Ahmed's left with $12.

step-by-step explanation:

starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.