Four cups of a salad blend containing 40% spinach is mixed with an unknown amount of a salad blend containing 55% spinach. The resulting salad contains 50% spinach. How many cups of salad are in the resulting mixture? 8 9 12 13

12 cups of salad

Step-by-step explanation:

Let the unknown cups of salad in the mixture be x( unknown cup in 55% mixture)

Thus, we have the following expression that shows the number of salad in the resulting mixture;

4(40%) + x(55%) = (4+x)(50%)

= 0.4(4) + x(0.55) = 0.5(4 + x)

= 1.6 + 0.55x = 0.2 + 0.5x

0.2 -1.6 = 0.55x-0.5x

0.4 = 0.05x

x = 0.4/0.05

x = 8 cups of salad

So the number of salad cups in the resulting mixture = x + 4 = 8 + 4 = 12 cups of salad

180 square centimeters

step-by-step explanation:

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.