You have to remember P.E.M.D.A.S. when doing problems like this.
Drew used PEMDAS so we know he isn't wrong. However, Sam didn't use PEMDAS. She multiplied 2&5 instead of raising 5 to the second.
The correct answer for Sams' problem would be 30.
Hope this helps! :)
Answer:
5n-28
Step-by-step explanation:
28-6n+7(2n-8)-3n
28-6n+14n-56-3n
28+8n-56-3n
28-56+8n-3n
-28+5n
5n-28
2 trench fish and 8 carp fish
Answer:
405
Step-by-step explanation:
To find sample size, use the following equation, where n = sample size, za/2 = the critical value, p = probability of success, q = probability of failure, and E = margin of error.

The values that are given are p = 0.84 and E = 0.03.
You can solve for the critical value which is equal to the z-score of (1 - confidence level)/2. Use the calculator function of invNorm to find the z-score. The value will given with a negative sign, but you can ignore that.
(1 - 0.9) = 0.1/2 = 0.05
invNorm(0.05, 0, 1) = 1.645
You can also solve for q which is 1 - p. For this problem q = 1 - 0.84 = 0.16
Plug the values into the equation and solve for n.

Round up to the next number, giving you 405.