Answer:
86%
Step-by-step explanation:
Let g represent the mean mark for the 10 girls in the class. Then the mean mark for the class was ...
10g +20(62%) = 30(70%)
g = 3(.7) -2(.62) . . . . . . . . . divide by 10 and subtract 2(.62)
g = .86 = 86%
The mean mark for girls was 86%.
_____
You can do this in your head if you consider it in terms of deviations from the mean. The second equation above can be rewritten and factored as ...
g = 70% +2(70% -62%)
That is, because there are 2 boys for every girl, the girl's score is above the mean by an amount that is 2 times the amount that the boy's score is below the mean. The boys' score is below by 8%, so the girls' score is above by 16%, so is 86%.
Answer:
the greatest common factor is 3
Answer:
-5
Step-by-step explanation:
x² - 4x - 45 = 0
(x - 9)(x + 5) = 0
x = 9 or -5
x² - 25 = 0
(x + 5)(x - 5) = 0
x = 5 or -5
-5 is a common factor between both of them
Two and three hundredths. I hope this helped, also by numbers do u mean in expanded form? Because that would be 2 + 0.03 .
<span>The urn contains 2 purple balls and 4 white balls. The player pay $4 for start the game and get $1.5 for every ball drawn until one purple ball is drawn. The maximal revenue would be $7.5 when 4 white balls and 1 purple balls are drawn.
If the purple ball is p and white ball is w, t</span>he possible sample space of drawings are {p, wp, wwp, wwwp, wwwwp}
<span>1. Write down the probability distribution for the player earning
The player earning </span>for each event depends on the number of balls drawn subtracted the ticket price.<span>
p= 2/6
The player earnings would be: 1*$1.5 -$4= - $2.5
wp= (4*2)/(6*5) = 4/15
</span>The player earnings would be: 2*1.5- $4= - $1
wwp= (4*3*2)/(6*5*4)= 1/5
The player earnings would be: 3*$1.5 -$4= $0.5
wwwp= (4*3*2*2)/(6*5*4*3*2)= 2/15
The player earnings would be: 4*$1.5 -$4= $2
wwwwp= (4*3*2*2*1)/(6*5*4*3*2*1) = 1/15
The player earnings would be: 5*$1.5 -$4= $3.5
2. Find its expected value
The expected value would be:
chance of event * earning
You need to combine the 5 possible outcomes from the number 1 to get the total expected value.
Total expected value= (1/3 * - 2.5)+ (4/15*-1) + (1/5*0.5) + (2/15 *2) + ( 1/15 *3.5)=
(-12.5 -4 + 1.5 + 4 + 3.5) /15= -$7.5
This game basically a rip off.
