Answer:
Let x be the number of bottles of water that Yui buys, and let y be the number of sports drinks she buys.
Since Yui buys a total of 6 bottles of water and sports drinks, we know that:
x + y = 6
We also know that each bottle of water costs $1.50 and each sports drink costs $2.50, and that Yui spends a total of $10. Therefore, we can write another equation based on the total cost:
1.5x + 2.5y = 10
We now have a system of two equations with two variables:
x + y = 6
1.5x + 2.5y = 10
To solve for x and y, we can use substitution. Rearranging the first equation, we get:
x = 6 - y
Substituting this expression for x into the second equation, we get:
1.5(6 - y) + 2.5y = 10
Expanding and simplifying, we get:
9 - 1.5y + 2.5y = 10
Combining like terms, we get:
y = 2
Substituting this value of y back into the equation x + y = 6, we get:
x + 2 = 6
Solving for x, we get:
x = 4
Therefore, Yui buys 4 bottles of water and 2 sports drinks.