The ratio of boys to girls is
12:24
(which is already one statement)
the ratio, simplified, is
1:2
(ratio are like fractions, which is how I was able to "simplify" it)
So the first thing you would have to is to find a common denominator so a common denominator between 11 and 15 is 165. 3/11 * 15 =45/165 next you would do 7/15 * 11=77/165 no that both denominators are the same we add the numerator but the denominator stays the same so 45/165 + 77/165 = 122/165
and since it can't be reduced any more 122/165 is your answer.
hope this helps :)
Answer:
D)
Step-by-step explanation:
ASSUMING NORMAL DISTRIBUTION, LESS THAN 10% AT LOWER END
OF 15.34 MEANS [DENOTING MEAN BY M AND Standard Deviation. BY S]
M±AS=20%....................M-AS=15.34
FOR 20% LEVEL .......A=1.281........FROM TABLES
M-1.281×S=15.34............................1
SIMILARLY
M±BS=40%...................M+BS=16.31
FOR 40% LEVEL .............B=0.841...................FROM TABLES
M+0.841×S=16.31.............................2
EQN.2 - EQN.1
2.122×S=0.97
S=0.457=0.46
M=15.926= 15.93
HENCE, D IS THE ANSWER
that is D. μ = 15.93, σ =.46
-0.37 is negative thirtyseven-hundredths, so in a fraction that would be -

. 37 is a prime number, so it isn't divisible by anything, meaning <span>
- 
is in simplest form.</span>