Answer:
Step-by-step explanation:
⇒ 
or
(Answer)
x = number of 1-cent stamps
y = number of 8-cent stamps
z = number of 12-cent stamps
We have 31 stamps all together, so x+y+z = 31.
"I have 4 more 1-cent stamps than 8-cent stamps" means we have the equation x = y+8. Whatever y is, add 8 to it to get x. Solve for y to get y = x-8.
You also have "twice as many one cent stamps as 12 cent stamps", so x = 2z. Solving for z gets you z = 0.5x
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x+y+z = 31
x+x-8+z = 31 ... y replaced with x-8
x+x-8+0.5x = 31 ... plug in z = 0.5x
2.5x-8 = 31
2.5x = 31+8
2.5x = 39
x = 39/2.5
x = 15.6
Your teacher made a typo somewhere because we should get a positive whole number result for x (since x is a count of how many 1-cent stamps we have).
Answer:
area = 3
Step-by-step explanation:
area of a triangle = 1/2 base x height
1/2 x 3 x 2 = 1/2 x 6 = 3
Since there is 7 water bottles in a package and the total price is 5.60, you divide 7 by 5.60 which gives you 1.25 per bottle
It will take 40 minutes.
To solve, divide 60 by 3. 60 is how many minutes there are in a minute. 3 is how long it takes to paint 2/5 of the room. We do not need to use the number 2/5 in this situation. Now back to 60 divided by 3. The answer is 20 minutes. Now multiply 20 by 2 to get 2/3 of an hour. Therefore, it takes 40 minutes to paint 2/5 of a room.
