Boys : Girls = 2:7
let the no. of boys be x
so no of girls = 250+x
so, x:(250+x) = 2:7
x/(250+x) = 2/7
7x = 500+2x
7x-2x = 500
x = 500/5 =100
Step-by-step explanation:
z = (specific score - mean) / standard deviation
in our case
z = (105 - 101)/4.2 = 4/4.2 = 0.952380952... ≈ 0.95
as z-tables usually round the z-scores to hundredths.
Answer: -11
Step-by-step explanation:
+(-8) can be simplified to -8 because when you multiply a positive sign by a negative sign, the outcome is a negative sign. So your problem is -3-8= and the answer is -11 because when two numbers with the same sign are subtracted/added by each other, the numbers just get added and the sign stays the same. If you're still confused, use a number line. Hope this helps!
