Let 
be the 20 marks of the boys, and 
be the 10 marks of the girls.
We know that the global mean was 70, meaning that
Multiplying both sides by 30 we deduce that the sum of the scores of the whole classroom is
By the same logic, we work with the marks of the boys alone: we know the average:
And we deduce the sum of the marks for the boys:
Which implies that the sum of the marks of the girls is 
And finally, the mean for the girls alone is
x - y = - 11 .............( 1 )
y + 7 = - 2x ...............( 2 )
from equation ( 1 )
x - y = - 11
x = -11 + y ...........( 3)
putting x in equation ( 2 )
y + 7 = - 2 x
y + 7 = -2 ( -11 + y ) y + 7 = 22 - 2 y y + 2 y =22 - 7
3 y = 15 y = 15 / 3
putting value of y in equation 3
x = -11+ ( 13 /5 ) x = -33 /3 + 15 / 3 ( l.c.m)
x = -17 / 5
check
x = -11 + y
- 17 / 5 = -11 + 13 / 5
-17 /5 = -17 / 5
Answer:
D) 2p+14/p
Step-by-step explanation:
Answer:
Sample Response: First, the like terms had to be combined using the lowest common denominator (LCD). Then the subtraction property of equality was used to isolate the variable term. Finally, both sides of the equation were multiplied by the reciprocal of the coefficient to solve for a.
Step-by-step explanation:
Answer:
294 cubic ft.
Step-by-step explanation:
All you do is just multiply the length, width, and height!
3 × 14 × 7 = 294
hopefully this helped :3
