Answer:
Notebooks: $2.75 each; pens: $1.10 each
Step-by-step explanation:
Let n and p represent the unit cost of notebooks and the unit cost of pens.
Then 3n + 2p = $10.45, and 4n + 6p = $17.60.
Let's use elimination by addition/subtraction to find n and p.
Multiplying the first equation by -3, we get -9n - 6p = -$31.35
and then combine this with the second: 4n + 6p = $17.60
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Then, -5n = -$13.75
Dividing both sides by 55, we get n = $13.75 / 5, so we now know that n = $2.75. Each notebook costs $2.75.
Subbing $2.75 for n in the first equation, we get:
3($2.75) + 2p = $10.45, or
$8.25 + 2p = $10.45
Solving for p, we get p = $2.20 / 2 = $1.10.
Each pen costs $1.10.
It is increase, because 15 is less than 18. Other way around, if the question is 18 to 15 yards, then that would be decrease, because it is getting smaller.
Rent all
55.5/3 = 18.5
74/4 = 18.5
it costs 18.5 per day
1. y = 18.5 x where y =cost and x=days
A-1
10.99 per 1/2 day
10.99 * 2 =21.98 per day
2. it costs 21.98 per day from A-1
Rentall is the better deal because it is only 18.50 per day versus 21.98 per day
Answer:
a) the probability of A students study for more than 10 hours per week
P(X>10) = 0.117
b) The probability that an student spends between 7 and 9 hour
P(7<x< 9) = 0.9522
Step-by-step explanation:
Step(I):-
Let 'X' be random variable of the normal distributed with a mean of 7.5 hours and standard deviation of 2.1 hours
mean of the Population is = 7.5 hours
standard deviation of the Population = 2.1 hours
Z = 1.1904
The probability of A students study for more than 10 hours per week
P(X>10) = 0.5-A(Z₁) = 0.5 -A(1.1904) = 0.5 - 0.3830 = 0.117
Step(ii):-
Put x=7
put x=9
The probability that an A student spends between 7 and 9 hour
P(7 < x< 9) = A(9) - A(7)
= 0.7142 +0.238
= 0.9522