Respuesta :
Answer:
Catherine's sister ate 2/15 gallons of the ice cream.
[tex]\displaystyle \frac{2}{15}[/tex].
Step-by-step explanation:
Let [tex]x[/tex] be the amount of ice cream that Catherine's sister ate, in gallons.
- Original amount: 1 gallon.
- What Catherine ate: [tex]\displaystyle \frac{1}{5}[/tex] gallons.
- What Catherine's sister ate is assumed to be [tex]x[/tex] gallons.
- What's left: [tex]\displaystyle \frac{2}{3}[/tex] gallons.
Consider the relationship:
[tex]\text{Original amount - What Catherine ate - What Catherine's Sister ate}\\ =\text{ What's left.}[/tex].
That is:
[tex]\displaystyle 1- \frac{1}{5} - x = \frac{2}{3}[/tex].
Add [tex]x[/tex] to both sides of this equation:
[tex]\displaystyle 1 - \frac{1}{5} = \frac{2}{3} +x[/tex]
Substract [tex]\displaystyle \frac{2}{3}[/tex] from both sides:
[tex]\displaystyle 1 - \frac{1}{5} - \frac{2}{3} = x[/tex].
Convert the denominator of all three numbers on the left-hand side to [tex]3 \times 5 = 15[/tex]
[tex]\displaystyle \frac{15}{15} - \frac{3}{15} - \frac{10}{15} = x[/tex].
[tex]\displaystyle x = \frac{2}{15}[/tex].
In other words, Catherine's sister ate [tex]\displaystyle \frac{2}{15}[/tex] gallons of the ice cream.
To solve this, we need to add the 1/5 of the ice cream to the 2/3 left of ice cream to find out how much her sister ate.
First, we need a common denominator. We can multiply 3 by 5 to get a common denominator easiest, since they are both multiples of it.
3*5=15
Now multiply the numerators by the amount the denominators were multiplied by.
1*3=3 so 3/15
2*5=10 so 10/15
Now, add them together.
10/15+3/15= 13/15.
Finally, subtract that amount from the original full amount of ice cream (15/15) to get the amount her sister ate, since that is the only unknown value left.
15/15-13/15=2/15.
Because 15 isn’t divisible by 2, we can’t simplify this fraction anymore.
Her sister ate 2/15 of a gallon of ice cream.
Hope this helps!