You can't simplify it because no whole number will go equally into 7
Answer:
95
Step-by-step explanation:
If the mean is 400 and the standard deviation 12.5. It means that a range between 375 and 425 is the mean +- 2 standard deviations
400 - 12.5*2 = 375
400 + 12.5*2 = 425
Which means the probability is 95%
When you are looking for +- 1 deviation standard the probability is 68, and for +- 3 the probability is 99.7
There is a more complex explanation based on Z, but assuming you are only applying 68-95-99.7 rule this should be enough.
Answer:


Step-by-step explanation:
<em>The question is mixed up with details of another question. See comment for original question</em>
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<u>Given</u>




Solving (a): Solve for time
We have:

Cross multiply

Make t the subject

Solving (b): Solve for distance
We have:

Cross multiply


Answer: See explanation
Step-by-step explanation:
Total number of children = 369
Percentage of children on museum trip = 20%
Number of children on museum trip = 20/100 × 369
= 1/5 × 369
= 73.8 = 74 approximately
Number of children in school = 369 - 73.8 = 295.2 = 295 approximately