The answer is 5. Work backwards: first add 7 to 9, then divide by 2, then subtract 3.
9+7=16
16/2=8
8-3=5
Cross Check:
5+3=8
8*2=16
16-7=9
Final Answer: 5
Looking at the two black dots
5 bulbs cost $9
Divide total cost by number of bulbs bought:
9 / 5 = $1.80 per bulb.
10 bulbs cost $18
Divide total cost by number of bulbs bought:
18 / 10 = $1.80 per bulb
The cost for one bulb is $1.80
Answer:
The approximate volume is 
Step-by-step explanation:
we know that
The exact volume of the cylinder is
so
To find the approximate volume of the cylinder, substitute the term 
by the approximate value of 
and then multiply
so
Answer: Choice C and Choice D
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Explanation:
- Choice A doesn't work because it the $1 should be $7 instead.
- Choice B doesn't work because it should be Elena spending $7 total on 3 notebooks and a $1 pen. The x is the amount per notebook.
- Choice C does work. If x is the number of grapes Noah gives each friend, then 3x is the total amount Noah gives over. Then 3x+1 is the number of grapes total. That +1 at the end is the grape Noah eats. We end up with 3x+1 = 7 because Noah starts off with 7 grapes.
- Choice D works also. The x is the number of hours for math, science and history each. So 3x is the combined time of those three classes. Add on 1 to get 3x+1 to represent all 7 hours, ie 3x+1 = 7.
- Choice E does not work. If it was her spending $7 on 3 markers and a $1 pen, then it would work.
