Mean=total/the number of values =>total=mean*the number of values
the total of the first set of 8 numbers is : total=8*8=64
the total of the second set of 12 numbers is: 12m
the total of the 20 numbers is: 64+12m
the mean of the 20 number is: (64+12m)/20=5
solve for m: 64+12m=100
12m=36
m=3
Answer:
5.714 liters of the 5% solution and 4.286 of the 40%.
Step-by-step explanation:
Let x be the volume of 40% solution and y = volume of the 5% solution.
x + y = 10
0.40x + 0.05y = 0.20(x + y)
From the first equation x = 10 -y so we have:
0.40(10 - y) + 0.05y = 0.20( 10 - y + y)
4 - 0.40y + 0.05y = 2
-0.35y = -2
y = 5.714 liters of the 5%.
and x = 10 - 5.714 = 4.286 liters of the 40% solution.
Step-by-step explanation:
Answer:
1.35kg
Step-by-step explanation:
450g : 6 people
x : 18 people
To get from 6 to 18, multiply by 3 so do the same to the other side
450 × 3 = 1350g
To convert from g to kg divide by 1000
1350 ÷ 1000 = 1.35kg
Answer: -8 and -4
This is something you do through trial and error. Making a list or a table like shown below might help.
Split it into 7 triangles. Half-base of each is 2 so the distance of center to the midpoint of the base is (Pythagoras) square root of (4.62 - 22) = 4.162 triangle is this times 2, and with 7 triangles multiply also by 7 to get an approximate area of 58 sq in.
