Let's take the number as x.
two-fifths of a number = 2x / 5
decreased by 3 = (2x/5) - 3
(2x/5) - 3
(2*25/5) - 3
(2*5) - 3
10 - 3
7
Answer:
A
Step-by-step explanation:
Number of pounds of macadamia nuts is 8 pounds and number of pounds of almonds is 4 pounds.
<u>Step-by-step explanation:</u>
Step 1:
Given total pounds of mixture = 12 pounds, cost of macadamia nuts per pound = $9, cost of almonds per pound = $5.25, total cost of mixture per pound = $7.75.
Let number of pounds of macadamia nuts be x and number of pounds of almonds be 12-x.
Step 2:
Form an equation using the above information.
⇒ 9x + 5.25 (12-x) = 12 × 7.75
⇒ 9x + 63 - 5.25x = 93
⇒ 9x - 5.25x = 30
⇒ 3.75x = 30
⇒ x = 8
Number of macadamia nuts is 8 pounds.
Step 3:
Calculate number pounds of almonds
⇒ Number of pounds of almonds = 12 - x = 4 pounds.
Answer:
Check the explanation
Step-by-step explanation:
Following table shows the calculations:
Delta, X Southwest , Y X^2 Y^2 XY
45.96 38.76 2112.3216 1502.3376 1781.4096
46.8 45.41 2190.24 2062.0681 2125.188
47.93 15.7 2297.2849 246.49 752.501
51.78 49.58 2681.1684 2458.1764 2567.2524
52.17 44.34 2721.7089 1966.0356 2313.2178
47.36 18 2242.9696 324 852.48
Total 292 211.79 14245.6934 8559.1077 10392.0488
Sample size: n =6
Now



The coefficient of correlation is :

Count change of signs to tell positive roots
then replace x with -x and evaluate, then count change in sign for negative roots
initially
+, -, -, +, +, -
3 changes
3 or 1 positive roots
replacing x with -x
-,-,+,+,-,-
2 changes
2 or 0 negative roots
B is answer