Answer:
2 hours
Step-by-step explanation:
270 = (70+65) * t
270= 135t
t = 2
Answer:
x = 5/2 thì y = 35 và x = -5 thì y = 5
Step-by-step explanation:
thay y = 4x + 25 vào phương trình y = 2x ^ 2 + 9x ta có:
4x + 25 = 2x ^ 2 + 9x
⇒2x ^ 2 + 5x - 25 = 0
⇒ x = 5/2 và x = -5
thay x = 5/2 vào phương trình y = 4x + 25 ⇒ y = 4*(5/2) + 25 = 35
thay x = -5 vào phương trình y = 4x + 25 ⇒ y = 4*(-5) + 25 = 5
Answer:
x = -2
Step-by-step explanation:
2 (3x+11)=10
Divide each side by 2
2/2 (3x+11)=10/2
3x+11 = 5
Subtract 11 from each side
3x+11-11 = 5-11
3x = -6
Divide each side by 3
3x/3 = -6/3
x = -2
What problem I don't see anything
Answer:
A) 34.13%
B) 15.87%
C) 95.44%
D) 97.72%
E) 49.87%
F) 0.13%
Step-by-step explanation:
To find the percent of scores that are between 90 and 100, we need to standardize 90 and 100 using the following equation:

Where m is the mean and s is the standard deviation. Then, 90 and 100 are equal to:

So, the percent of scores that are between 90 and 100 can be calculated using the normal standard table as:
P( 90 < x < 100) = P(-1 < z < 0) = P(z < 0) - P(z < -1)
= 0.5 - 0.1587 = 0.3413
It means that the PERCENT of scores that are between 90 and 100 is 34.13%
At the same way, we can calculated the percentages of B, C, D, E and F as:
B) Over 110

C) Between 80 and 120

D) less than 80

E) Between 70 and 100

F) More than 130
