Answer:
Step-by-step explanation:
The half-life of the radioactive substance can be determined through teh equation ln 2 = k (t 1/2) where k is equal to ln (1/(1-0.58)) / 3. Hence t 1/2 is equal to 2.40 days. To decay to 10% of the original amount, ln (1/0.90) / ( ln2) / 2.40, time is equal to 0.37 days.
Answer:
see explanation.
Step-by-step explanation:
2(10 * 4 * 7) is a surface area.
7 * 4 * 10 is volume.
2(10 * 4 + 10 * 7 + 4 * 7) is surface area.
10 + 4 + 7 is neither.
2 * 7 * 4 + 2 * 10 * 7 + 2 * 4 * 10 is neither.
hope this helps.
Answer:
40,320
Step-by-step explanation:
He can pick any one of the eight for the first examination.
He can pick any one of the remaining 7 for the 2nd examination.
He can pick any one of the remaining 6 for the 3rd examination.
...
He can pick any one of the remaining 2 for the 7th examination.
There's one left for the 8th examination.
Thus, there are 8×7×6×5×4×3×2×1 = 8! = 40,320 different possible orders in which the tubes can be examined.
Answer:
12
Step-by-step explanation:
The ratio of cars to trucks to motorcycles is $4:3:2.
If there are $42$ cars and trucks total,
To get how many motorcycles are there
Sum up the ratio of cars and trucks 4:3= 4+3 = 7
Sum up the ratio of cars and trucks and motorcycles
4+3+2 =9
Let the total number of cars and trucks and motorcycles be represented as A
The total number of cars and trucks in the question is 42
(7/9) x A = 42
7A/9 = 42
cross multiply
7A = 42×9 = 378
A= 378/7 = 54
The total number of cars and trucks and motorcycles is 54
To get the number of motorcycles can be calculated through
a. The total number of cars and trucks and motorcycles subtracted by the number of cars and trucks = 54-42=12 or use the ratio which is
2/9 × 54 = 2×6=12
