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ikadub [295]
3 years ago
13

50 students each did a mathematics test. the mean score for these 50 students was 8.4. there were 30 boys. the mean score for th

ese bots were 8.25. workout the mean score for the girls.
Mathematics
1 answer:
Angelina_Jolie [31]3 years ago
7 0

[(30 x 8,25) + (20 x n)] / 50 = 8,4

247,5 + 20 x n = 420

n = (420 - 247,5) : 20

n = 8,625

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2k - 2j when j=4&k=6 replace the variable with the given amount and solve the problem​
eimsori [14]

Answer:

4

Step-by-step explanation:

first, plug in 6 for k.<em> (</em><em>i</em><em>t</em><em> </em><em>doesn't</em><em> </em><em>matter</em><em> </em><em>which</em><em> </em><em>value</em><em> </em><em>you</em><em> </em><em>plug</em><em> </em><em>in</em><em> </em><em>first</em><em>;</em><em> </em><em>you can start with j </em><em>o</em><em>r</em><em> </em><em>k</em><em>,</em><em> </em><em>but i'm just </em><em>s</em><em>t</em><em>a</em><em>r</em><em>t</em><em>i</em><em>n</em><em>g</em><em> </em><em>with</em><em> </em><em>k</em><em> </em><em>since</em><em> </em><em>that</em><em> </em><em>is</em><em> </em><em>the</em><em> </em><em>v</em><em>a</em><em>r</em><em>i</em><em>a</em><em>b</em><em>l</em><em>e</em><em> </em><em>that</em><em> </em><em>comes</em><em> </em><em>first</em><em> </em><em>in</em><em> </em><em>the</em><em> </em><em>expression</em><em>)</em>

2k - 2j => 2(6) - 2j

then plug in 4 for j.

2(6) - 2j => 2(6) - 2(4)

now your expression is 2(6) - 2(4). simplify by multiplying 2(6) and then -2(4) <em>(</em><em>again</em><em>,</em><em> </em><em>it</em><em> </em><em>doesn't</em><em> </em><em>matter</em><em> </em><em>which</em><em> </em><em>one</em><em> </em><em>you</em><em> </em><em>multiply</em><em> </em><em>first</em><em>,</em><em> </em><em>as</em><em> </em><em>long</em><em> </em><em>as</em><em> </em><em>you</em><em> </em><em>make</em><em> </em><em>sure</em><em> </em><em>that</em><em> </em><em>the</em><em> </em><em>minus</em><em> </em><em>sign</em><em> </em><em>between</em><em> </em><em>2</em><em>(</em><em>6</em><em>)</em><em> </em><em>and</em><em> </em><em>2</em><em>(</em><em>4</em><em>)</em><em> </em><em>gets</em><em> </em><em>attached</em><em> </em><em>to</em><em> </em><em>the</em><em> </em><em>2</em><em> </em><em>in</em><em> </em><em>2</em><em>(</em><em>4</em><em>)</em><em>.</em><em>)</em>

2(6) - 2(4) => 12 - 2(4)

12 - 2(4) => 12 - 8

subtract 8 from 12.

12 - 8 = 4

your answer is 4, therefore when j = 4 and k = 6, 2k - 2j = 4.

i hope this helps! have a nice day <3

8 0
3 years ago
There is a cup of water is it half full or half empty
Allushta [10]
Either it's whatever you prefer to be
3 0
4 years ago
When Scott got his dog Arfus, it weighed
Leokris [45]
It gained 2 lb. because if you subtract 8-6 you would get 2. So Arfus gained 2 lb.
6 0
3 years ago
How many ninths does it take to make the same amount as 1/3
malfutka [58]
3/9 This is because one third of nine is three. That is also why 3x3=9.
6 0
3 years ago
-x+y=0 <br> 4x-3y=3<br> substitution
s2008m [1.1K]

Answer:

x= 3

y= 3

Step-by-step explanation:

Step: Solve−x+y=0 for y:

−x+y=0

−x+y+x=0+x (Add x to both sides)

y=x

Step: Substitute x for y in 4x−3y=3:

4x−3y=3

4x−3x=3

x=3 (Simplify both sides of the equation)

Step: Substitute 3 for x in y=x:

y=x

y=3

4 0
3 years ago
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