Answer:
x=280
Step-by-step explanation:
We have, 15% × x = 42
or,
15
100
× x = 42
Multiplying both sides by 100 and dividing both sides by 15,
we have x = 42 ×
100
15
x = 280
If you are using a calculator, simply enter 42×100÷15, which will give you the answer.
Answer: 2.28 %
Step-by-step explanation:
Given : Mean : 
Standard deviation :
The formula to calculate the z-score :-

For x = 72

The p-value = 

In percent, 
Hence, the percentage of pediatricians work more than 72 h per week = 2.28 %