Solve the simultaneous equations 3x+y=172 x+y=12
1 answer:
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Answer:
(x, y) = (80, -68)
Step-by-step explanation:
Subtract the second equation from the first.
(3x +y) -(x +y) = (172) -(12)
2x = 160 . . . . . . . . . simplify
x = 80 . . . . . . . . . divide by 2
y = 12 -x = 12 -80 = -68 . . . . . find y from the second equation
The solution is (x, y) = (80, -68).
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For this case we have that the complete question is:
There were 20 drinks in a cooler. Joey drank 15% of the drinks. Sandra drank 1/5 of the drinks. Hannah drank 1/4 of the drinks. Tammy drank 30% of the drinks. How many drinks are left in the cooler? a 0 b 2 c 5 d 9
We propose a rule of three:
20 ---------> 100%
x ------------> 15%
Where the variable "x" represents the amount of drinks equivalent to 15%.
So, Joey drank 3 drinks.
On the other hand, we have that Sandra drank of the drinks:
Thus, Sandra drank 4 drinks.
In addition, Hannah drank of the drinks:
So Hannah drank 5 drinks.
Finally, Tammy drank 30% of the drinks:
20 ---------> 100%
y ------------> 30%
Where the variable "y" represents the amount of drinks equivalent to 30%.
So Tammy drank 6 drinks.
Adding up we have:
So:
Thus, 2 drinks remain in the refrigerator.
Answer:
Option B