67 ÷ 10 x 4 = 26.8 hours for her to eat 67 cookies
Answer:
257 is prime.
Step-by-step explanation:
To evaluate if a number is prime, we just need to evaluate it for the prime numbers that are equal or lesser than the said number's square root.
In this case, √257 = 16.03 so we just need to see if 257 is divisible by <u>2, 3, 5, 7, 11 and 13</u> (the prime numbers that come before 16)
- 257 is odd, so it is not divisible by 2.
- The sum of its digits is 14, therefore, it is not divisible by 3.
- 257 ends in 7, therefore it's not divisible by 5.
- 257/ 7 = 36.71 so it's not divisible by 7.
- 257/ 11 = 23.36 so it's not divisible by 11
- Finally 257 / 13= 19.76 so it's not divisible by 13.
Therefore, 257 is prime.
Answer:
y = 2x - 3
Step-by-step explanation:
We are asked to find the equation of a straight line
Step 1: find the slope
( 2 , 1) ( 5 , 7)
x_1 = 2
y_1 = 1
x_2 = 5
y_2 = 7
Insert the values into the equation
m = (y_2 - y_1 )/ (x_2 - x _1)
m = (7 - 1 )/ (5 - 2)
m = 6/3
= 2
Step 2: substitute m into the equation
y = mx + c
y = 2x + c
Step 3 : sub any of the two points given into the equation
Let's use ( 2, 1)
x = 2
y = 1
y = 2x + c.
1 = 2(2) + c
1 = 4 + c
c = 1 - 4
c = -3
Step 4: sub c into the equation
y = 2x + c
y = 2x - 3
Answer:
A. 18÷2/9
Step-by-step explanation:
A. 18÷2/9
B. 18×2/9
C. 2/9÷18
D. 9/2÷18
Let
Total length of box = 18 inches
Thickness of each book = 2/9 inches
Number of books that will fit into the box = x
Number of books that will fit into the box = Total length of box ÷ Thickness of each book
x = 18 ÷ 2/9
= 18 × 9/2
= 162/2
= 81 books
The correct answer is A. 18÷2/9
