Answer:
idk but 2 looks correct humph
Answer:
86%
Step-by-step explanation:
Let g represent the mean mark for the 10 girls in the class. Then the mean mark for the class was ...
10g +20(62%) = 30(70%)
g = 3(.7) -2(.62) . . . . . . . . . divide by 10 and subtract 2(.62)
g = .86 = 86%
The mean mark for girls was 86%.
_____
You can do this in your head if you consider it in terms of deviations from the mean. The second equation above can be rewritten and factored as ...
g = 70% +2(70% -62%)
That is, because there are 2 boys for every girl, the girl's score is above the mean by an amount that is 2 times the amount that the boy's score is below the mean. The boys' score is below by 8%, so the girls' score is above by 16%, so is 86%.
There 7 blocks of hundreds which means each such block is equivalent to 100.
There are 5 blocks of tens, which means each such block is equivalent to 10.
There are 8 blocks of ones, which means each such block is equivalent to 1.
The total of these blocks will be = 7(100) + 5(10) + 8(10) = 758
We can make several two 3-digit numbers from these blocks. An example is listed below:
Example:
Using 3 hundred block, 2 tens blocks and 4 ones block to make one number and remaining blocks to make the other number. The remaining blocks will be 4 hundred blocks, 3 tens blocks and 4 ones blocks
The two numbers we will make in this case are:
1st number = 3(100) + 2(10) + 4(1) = 324
2nd number = 4(100) + 3(10) + 4(1) = 434
The sum of these two numbers is = 324 + 434 = 758
i.e. equal to the original sum of all blocks.
This way changing the number of blocks in each place value, different 3 digit numbers can be generated.
The fraction 3/9 is equivalent to 1/3.The fraction 3/9 is equal to 3÷9 and can also be expressed in decimal form as 0.333333.
Answer:
Look below
Step-by-step explanation:
Given that CDB is 90 degrees, ACB is 90 degrees, and ACD is 60 degrees, we can determine that DCB = 90-60 = 30 degrees.
This means triangle BCD is a 30-60-90 (angle measures) right triangle
The proportions of the sides (from smallest to largest) is
x:x√3:2x
We are given that BC = 6 cm. This means...
2x=6
x=3
This means DB is 3 cm and CD is 3√3 cm
Using the linear pair theorem, we can find that Angle CDA is 90 degrees. This means ACD is also a 30-60-90 triangle.
x=3√3
x√3=9
2x=6√3
Now we need to find AB
AB = AD + DB
AB = 9 + 3
AB = 12 cm
