90kg of sand had been puted in 3 bags but in 2+3+7=12 parts.
90kg/12=7.5kg
Small bag has 2 parts which is 7.5kg*2=15kg
Medium bag has 3 parts which is 7.5kg*3=22.5kg
Large bag has 7 parts which is 7.5kg*7=52.5kg
2:3:7=15kg:22.5kg:52.5kg
15kg+22.5kg+52.5kg=90kg
They are both equal because in decimals you can add thousands of zeros and it's still equal.
Answer:
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Step-by-step explanation:
Answer:
A. 
Step-by-step explanation:
We want to find the Z-score of
if the population mean is
,and the population standard deviation is
.
We use the formula:

We substitute the values to obtain:



The correct answer is A.