Which situation is an example of opposite quantities combining to make 0? A gift card had a balance of $20. Then, all $20 on the gift card was spent.

A swimmer was 6 feet below the surface of the water. Then she descended another 6 feet.

A container had 2.1 ounces of liquid. Then, 2.1 ounces of liquid was added to the container.

The temperature was - 5 degrees Fahrenheit. Then, the temperature decreased by 5 degrees.

Aregular hexagon rotates counterclockwise about its center. it turns through angles greater than 0° and less than or equal to 360°. at how many different angles will the hexagon map onto itself?

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test

Aquantity with an initial value of 3900 decays exponentially at a rate of 35% every hour. what is the value of the quantity after 0.5 days, to the nearest hundredth?