<span>mean: ( 9 + 7 + 6.5 + 7.5 + 7 + 8 + 5 + 6 + 7.5 + 8 ) : 10 = 7.15Variance:(Sigma)² = ( 1.85² + 0.15² + 0.65² + 0.35² + 0.15² + 0.85² + 2.15² + 1.15² + 0.35² + 0.85² ) : 10 ≈ 1.15Answer: C ) 1.15</span>
Answer: He can predict that 420 students will be in support of the purchase.
Step-by-step explanation:
Since Randy surveyed one student out of every 5 he came across in the cafeteria, it means that if he came across five people, he will survey one, if he came across ten students, he will survey 2 and so on.
If then he surveyed a total of 140 students, then we can actually multiply the number by 5 to know the exact number of students he possibly came across in the cafeteria:
= 140 × 5
= Total of 700 students
If 84 out of the surveyed students supported the purchase, we can find what that figure represents in the total number of students in the cafeteria:
84/140 = x/700
We cross multiply
140 × X = 84 × 700
140X = 58,800
X = 58,800/140
X = 420 students
Therefore, he can predict that 420 students out of a total of 700 students in the cafeteria will be in support of the purchase of the P.E equipment
Do you need for both or just one?
Answer:
See explanation
Step-by-step explanation:
8x = 3y + 38
24= 6y + 9x
Rearrange;
3y - 8x = -38 * 2 -------(1)
6y + 9x = 24 * 1 -------(2)
6y - 16x = -76 -------(3)
6y + 9y = 24 -------(4)
Subtract (4) from (3)
-25y = -100
y= 100/25
y = 4
Substitute y =4 into(1)
3y - 8x = -38
3(4) - 8x = -38
12 -8x = -38
-8x = -38 - 12
x = 50/8 = 6 2/8
2) 6 = 2x + y
7x = 3 - 3y
Rearrange;
2x + y = 6 * 3 --------(1)
7x + 3y = -3 * 1 --------(2)
6x + 3y = 18 ---------(3)
7x + 3y = -3 ---------(4)
Subtract (4) from (3)
-x = 21
x = -21
Substitute x = -21 into (1)
2x + y = 6
2(-21) + y = 6
-42 + y = 6
y = 6 + 42
y = 48
3)
11x = 5 + 10y
7y = -2x +45
Rearrange
11x - 10y = 5 * 2 ---------(1)
2x + 7y = 45 * 11 ---------(2)
22x - 20y = 10 --------(3)
22x + 77y = 495 --------(4)
Subtract (4) from (3)
-97y = -485
y = 5
Substitute y =5 into (1)
11x - 10y = 5
11x - 10(5) = 5
11x - 50 = 5
11x = 5 + 50
11x = 55
x = 55/11
x = 5
