Answer:
20
Step-by-step explanation:
The cost of the x mangoes was ...
c = 10(x/4)
The revenue from the sale of mangoes was ...
r = 20(x-5)/5
The profit is the difference between revenue and cost:
10 = r - c = 20(x -5)/5 -10(x/4) = 1.5x -20 . . . . substitute and simplify
30 = 1.5x . . . . . add 20
20 = x . . . . . . . .divide by 1.5
The trader bought 20 mangoes.
_____
<em>Check</em>
He paid 20(10/4) = 50 naira. He sold the 15 good mangoes for 20/5(15) = 60 naira, so made a 10 naira profit.
Answer:
There are 320 students at Milton middle school.
Step-by-step explanation:
From the information provided, you can use a rule of three to find the total amount of students at Milton middle school as you know that there are 144 girls and they represent 45% of the students:
144 → 45%
x ← 100%
x=(144*100)/45
x=320
According to this, the answer is that there are 320 students at Milton middle school.
Situation satisfies the criteria for the use of hypergeometric distribution. Since no replacement is made, binomial distribution is not applicable (probability does not remain constant).
A=number of target wattage bulbs
B=number of non-targeted wattage bulbs
a=number of target wattage bulbs selected
b=number of non-targeted wattage bulbs selected
P(a,b)=C(A,a)*C(B,b)/C(A+B,a+b)
where C(n,x)=combination of x items chosen from n=n!/(x!(n-x)!)
For all following problems,
A+B=4+5+6=15
a+b=3 (selected)
(a) Target wattage = 75W
A=6, B=9, a=2, b=1
P(a,b,A,B)
=P(2,1,6,9)
=C(6,2)*C(9,1)/C(15,3)
=15*9/455
=27/91
(b) target wattage = each of the three
Probability = sum of probabilities of choosing 3 40,60,75-watt bulbs
P(3x40W)+P(3x60W)+P(3x75W)
Case (A,B,a,b)
3x40W (4,11,3,0)
3x60W (5,10,3,0)
3x75W(6,9,3,0)
P(3x40W)+P(3x60W)+P(3x75W)
=C(4,3)*C(11,0)/C(15,3)+C(5,3)*C(10,0)/C(15,3)+C(6,3)*C(9,0)/C(15,3)
=4*1/455+10*1/455+20*1/455
=34/455
Can also be solved by elementary counting, for example, for (a),
P(2x75W)
=C(3,2)*6/15*5/14*9/13
=(3)*6/15*5/14*9/13
=27/91 as before
