Mario puts 4 packets in 16 ounces.
For the coffee to be equally sweet, if he had a 32 cup,
just multiply both numbers by 2.
If he put 4 packets in 16 ounces,
you'd put 8 packets in 32 ounces.
By doubling the packets and the coffee, the coffee is equally sweet.
There is just more of it.
Sam puts 8 packets in only 31 ounces of coffee.
Since Sam puts as much sugar in less coffee, Sam's coffee is sweeter.