Answer:
30 students
Step-by-step explanation:
3 students = 10% of the class.
x students = 90% of the class.
(If more, less divides. Let x be the subject. Since we know 10% of the class already, we have to find the remaining 90% that is 100% - 10% = 90%.)
x = 90%/ 10% × 3 students. ( the percentage signs cancel out and so do the zero's.)
x= 9/1 × 3 students ( 9/1 is the same as 9)
x= 27 students
(To find the total, you must add the 10% of the students to the remaining 90% of the students in the class.)
Total number of students in the class = 27 students + 3 students
= 30 students
X should equal to 17 but i dont see what ben did...

difference between standard deviation and mean deviation
Answer:
Standard deviation is basically used for the variability of data and frequently use to know the volatility of the stock. A mean is basically the average of a set of two or more numbers. Mean is basically the simple average of data
Hope this helps!!

Answer:
Surface area is 300 in Squared
Step-by-step explanation:
2(lw + wh + hl) = rectangular Prism Formula
Length- 12
Width- 9
Height- 2
So just Substitute the values.
2( 12 x 9+ 9 x2 + 12 x 2) = ?
2(108 +18+ 24)
2 x 150
= 300