The correct answer choice is D.
Answer:
Marilee wants to earn an "A" in a class and needs an overall average of at least Her test grades are 88 , 92,100 , and 80 . The average of her quizzes is 90 and counts as one test grade. The final exam counts as 2.5 test grades. What scores on the final exam would result in Marilee's overall average of 92 or greater? (See Example 9
Given that the half life of 3H is 12.3 years.
The amount of substance left of a radioactive substance with half life of

after t years is given by

Therefore, the number of years it will take for 18% of the original tritinum to remain is given by

Therefore, the number of <span>years that the time could be read at night is 30.4 years.</span>
The answer is .1
........
Answer:
72 kg
Step-by-step explanation:
For concreatting a tower cement, sand, stones are in the ratio 1:2:4 For 144kg sand.. What amount of cement is required?
We are given the ratio
cement: sand:stones
= 1:2:4
The sum of proportion =
1 + 2 + 4 = 7
We are given the kg of sand = 144kg
Step 1
We find the total kg of cement, sand and stones = x
Using the proportion of sand,
2/7 of x = 144kg
2/7 × x = 144kg
2x/7 = 144kg
Cross Multiply
2x = 7 × 144kg
x = 7 × 144kg/2
x = 504kg
Therefore the total kg of cement, sand and stone = 504kg
Step 2
The amount of cement required is calculated as:
1/7 × 504 kg = 72 kg
Therefore, 72kg of cement is required.