Answer:
josh vendió 17 libros recaudando 306 dolares .
jessica vendió 255 libros recaudando 4590 dolares.
Step-by-step explanation:
Sustituimos por variables :
libros que vendió Jessica = x
libros que vendió Josh = y
entonces:
x + y = 272
Jessica vendió 15 veces mas libros que josh:
x = 15y
Reemplazamos en la anteriior ecuacion:
15y +y = 272
16y = 272
y = 17
Reemplazamos en la primela ecuacion :
x + 17 = 272
x = 255
For this case we have to rewrite the given expression algebraically:
the cube of a, is represented as: 
the square of b, is represented as:
Thus, the product of both expressions is:
And twice the product is represented as:
Answer:
2,000,000➕900,000➕30,000➕7,000➕
80➕2
The given data is
Scores: 90-99 80-89 70-79 60-69 50-59
Students: 3 7 12 4 4
Because we are to take the middle value for each group.
Therefore the total score is
Sx = 3*94.5 + 7*84.5 + 12*74.5 + 4*64.5 + 4*54.5 = 2245
The number of students is 3+7+12+4+4 = 30
The mean is
m =2245/30 = 74.833
Calculate (Sx - m)²
(Sx - m)² = 3*(94.5-74.833)² + 7*(84.5-74.833)² + 12*(64.5-74.833)²
+ 4*(64.5-74.833)² + 4*(54.5-74.833)² = 3896.7
Calculate the standard deviation
s = √(3896.7/29) = 11.592
Answer:
mean = 74.83
std. deviation = 11.59
