1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ELEN [110]
3 years ago
12

The mean mark is 70% there are 30 students 20 of which are boys with a mean mark if 62% what is the mean for girls

Mathematics
1 answer:
Anna007 [38]3 years ago
7 0

Answer:

This problem can be solved by working backwards.  

Average of 30 students = 70.

Total marks of all the 30 students = 30x70 = 2100

Out of these 30, average of 20 students = 62

Total marks of these 30 students = 30x62 = 1860

So the total marks of the remaining 10 students = 2100-1860 = 240

Hence the average of the remaining 10 students = 240/10 = 24



You might be interested in
Help me and I will give u brain..................​
Lemur [1.5K]
It would probably be B
6 0
3 years ago
Find the area of the surface generated by revolving the curve about the axis y = 9-x^2
Nat2105 [25]

The area of the surface generated by revolving the curve about the axis y = 9-x² is 12π

<h3>What is a revolution on a graph? or curve?</h3>

Surfaces of revolution are graphs of functions f(x,y) that rely exclusively on the distance from the origin of the point (x,y).

Polar coordinates (r,) are one approach to discuss such surfaces. A "surface of revolution" is formed by rotating a curve around an axis.

Consider a curve with coordinates x and z in the "x0" half of the Euclidean plane.

<h3>What is the calculation justifying the above answer?</h3>

y = √(9-x²)

⇒ dy = (-2x)/2√9-x²)

= -x/√(9-x²)

Note that surface area (s) is given as:

\int\limits^b_a {2\pi y} √1 + (dy/dx)² dx

= 2\pi \int_{1}^{-1} √9-x² * √[1 + (-x)/√9-x²)]dx

= 2π \int_{1}^{-1}3dx
= 6π [x]₋¹₁

= 6π (1-(-1)

= 6π (2)

= 12π

Learn more about revolving on a curve:
brainly.com/question/2293431
#SPJ4

6 0
1 year ago
You already know how to use inequalities to
Vladimir [108]

Answer: -4 <= x < 4. For the second answer, it’s -2 <= y < 5

Step-by-step explanation:

7 0
3 years ago
Read 2 more answers
Where do I put the parentheses:<br>7+3x4-1=39
allsm [11]
(7+3)x(4-2)=39
I hope that helps
8 0
3 years ago
Read 2 more answers
The area of a square is defined by, A(x) = x 2 - 6x + 9. What is the length of a side of the square?
Dmitriy789 [7]
A9x)  = x^2 - 6x + 9  = (x - 3)^2

length of a side = x - 3 
8 0
3 years ago
Other questions:
  • Identify as a direct variation, inverse variation or neither. y = 6x
    5·1 answer
  • Joe spends $8 on lunch and 6.50 on dry cleaning.He also buys 2 shirts that cost the same amount. Joe spends a total of $52.What
    15·1 answer
  • The height y of a ball (in feet) is given by the function y = – 15 x + 2x + 4
    8·1 answer
  • Point A is located at (0, -2) and is rotated 180°. What are the coordinates of point A'?
    7·2 answers
  • I need help on this question pls
    6·1 answer
  • Ratio of 2 cups to 10 cups?
    14·1 answer
  • Determine the standard form of the equation of the line that passes through (-7,8) and (0,-8)
    14·1 answer
  • Need help figuring out the answer got any tips??
    6·2 answers
  • Y=3x + 15<br>4X-3y =25<br>SOLVE BY SUBSITUTION​
    7·2 answers
  • Ashley rode her bicycle 29.4 miles in 4 hours. She rode the same number of miles each hour. How many miles did ride her bike in
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!