Answer:
74.72
Step-by-step explanation:
Given
mean
Standard deviation 
For Top 25%

and Z value for 75 % is 0.6744
Thus score which separates the Top 25% of students is


If we have 2 more blue pens than black pens, our blue pens can be rewritten as blue = 2 + black. Now we can set up an equation. Originally this equation would involve both blue and black, but since we only have 1 equation to set up, we can only have 1 unknown. That's why we base the number of blue pens on the number of black pens and do a substitution. So instead of blue + black = 94, we have (black + 2) + black = 94. That simplifies to 2 black + 2 = 94, and 2 black = 92. Now if we divide by 2, we get that the number of black pens is 46. If we have 2 more blue than black, the number of blue pens we have is 48. 46 + 48 = 94, so there you go!
Infinitely many solutions means that you have the same thing on both sides of the equation no matter what value of x you plug in, right?
We just need both sides to be 3x then, correct?
If a were equal to 3 and b were equal to 0, we'd have
3x = (3)x + 0
Which is essentially 3x = 3x
So that means a = 3 and b = 0 must work!
Let's say x = 5
3(5) = 3(5) + 0
15 = 15 + 0
15 = 15
That means that a = 3 and b = 0 is your final answer :)