Find the fraction suitable for the blank space:
3½ + (1½ × ) = 4½

2/3

Step-by-step explanation:

Since you need to find the mising number, I will give it the variable (v)

So the equation is now:

1½v is the same as 1½ x v

3½ + (1½v) = 4½

I need to undo addition so I subtract.  To undo you need to look at the sign at the front of the number, since there was no negative sign I can infer that 3½ is positive.  I need 3½ to cancel out and become 0, so I subtracted 3½ with 3½.  What you do to one side of the equal sign, do to the other.  4½ subtract 3½ is 1.

The equation is now:

1½v = 1

I need to undo multiplication, so I divide 1½ by 1½.  It cancels out, and I what you do to one side of the equal sign, you do to the other. 1 divides by 1½ is 2/3.  (I used a calculator for this part)

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.