E=number of eight cent stamps
t=number of ten cent stamps bought
w=number of 2 cent stamps bought
number of eight=number of ten
e=t
as many 2 cent as the other 2 combined
e+t=w or
2e=w=2t
total she bouthgt 4.40
4.40=440 cents
8e+10t+2w=440
solve for t or e, I solve for t
8t+10t+2(2t)=440
18t+4t=440
22t=440
divide 22
t=20
t=e
20=e
w=2e
w=2(20)
w=40
answer is
20 eight cent
20 ten cent
40 two cent
Step-by-step explanation:
78 76 67 66 80 77 77 84 74
correct them
First the 3.1 hr is one standard deviation away from the mean:
2.5 + 0.6 = 3.1 hr. then the one standard deviation away from the mean contains 68% of the total population. so the percent that is higher from 3.1 hr is
% higher 3.1 hr = ( 100 - 68) / 2
% higher 3.1 hr = 32 / 2
% higher 3.1 hr = 16 %
Answer:
the (x, y) pair solution to the system is: (-2, -4)
That is x = -2 and y = -4
Step-by-step explanation:
I presume there is a variable y missing in the first equation, and in fact the system looks like:
(1/2) x + (3/2) y = - 7
- 3 x + 2 y = -2
In such case, we proceed to multiply both sides of tye first equation by 6
6 (1/2) x + 6 (3/2) y = - 42
3 x + 9 y = - 42 and we add term by term this equation to the second one, so as to cancel out the term in x:
3 x + 9 y = - 42
- 3 x + 2 y = -2
_____________
11 y = - 44
divide both sides by 11 to isolate y
y = -44 / 11 = -4
Then with the value y = -4, now we replace it in the second equation to solve for x:
- 3 x + 2 y = - 2
- 3 x + 2 (- 4) = -2
- 3 x - 8 = - 2
add 8 to both sides
- 3 x = 6
divide both sides by (-3) to isolate x
x = 6 / (-3) = - 2
Therefore the (x, y) pair solution to the system is: (-2, -4)
That is x = -2 and y = -4
Answer:
-27-2x
Step-by-step explanation:
5-3x+x-32
(collect like terms)
5-32-3x+x
<h2><u><em>
-27-2x</em></u></h2>
