Set up the equation by writing the number of students in the ratio as a fraction:
3/4= (245-x)/x Cross multiply:
3x= 4(245-x) Multiply on right:
3x= 980-4x Add 4x on both sides:
7x= 980 Divide both sides by 7:
x= 140 this is how many girls there are. And:
245-140= 105= boys
The answer is B
A. 6(a+5)
=6a+30 not equivalent to 6a+15
B.3(2a+5)
=6a+15 is equivalent
C.3(3a+12)
=9a+36 not equivalent
D.6(a+12)
=6a+72 not equivalent
So your answer is B
The least (or lowest) common denominator of 3, 16 and 8 is 16. That already points us to answer A.
Checking for each fraction:
1/2 * 8/8 = 8/16
3/16 * 1/1 = 3/16
7/8 * 2/2 = 14/16
Yep. Answer A.
Answer:
a) 6.68th percentile
b) 617.5 points
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

a) A student who scored 400 on the Math SAT was at the ______ th percentile of the score distribution.



has a pvalue of 0.0668
So this student is in the 6.68th percentile.
b) To be at the 75th percentile of the distribution, a student needed a score of about ______ points on the Math SAT.
He needs a score of X when Z has a pvalue of 0.75. So X when Z = 0.675.



