Answer:
There would be 168 girls and 252 boys
Step-by-step explanation:
40% or 0.40 x 420 = 168
420 - 168 = 252
Answer:
25
Step-by-step explanation:
No. 1.5 is a whole number while 1.5% is a percent
<h2><u>
Answer with explanation</u>
:</h2>
Let
be the average life of light bulbs.
As per given , we have
Null hypothesis : 
Alternative hypothesis : 
Since
is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Formula for Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For
, we have

Using z-value table , Critical one-tailed test value for 0.06 significance level :

Decision : Since critical z value (1.5548) < test statistic (1.6180), so we reject the null hypothesis .
[We reject the null hypothesis when critical value is less than the test statistic value .]
Conclusion : We have enough evidence at 0.06 significance level to support the claim that the new filament yields a longer bulb life
64+(2x)=35(x-1)
expand
64+2x=35x-35
minus 2x from both sides
64=33x-35
add 35 to both sides
99=33x
divide both sides by 33
3=x
the number is 3