Sara was thinking of a number. Sara divides by 2, then adds 10 to get an answer of 6. What was the original number?
2 answers:
Answer:
-8
Step-by-step explanation:
We know that Sara has a number by which she divides by 2, added 10 and ended up with 6. We are then asked to find the original number she had in mind.
To solve, we need to go backwards, starting with the original number, and applying all the steps she did but with the opposite operation.
6 is her ended number, we know before she added 10, so subtract 10 from 6:
Now we know that she divided by 2, therefore multiply -4 by 2:
-8 was Sara's first number.
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V=x^3+5x^2-57x-189
Width: W=(x+3) in = 15 in →x+3=15
Solving for x:
x+3-3=15-3→x=12
With x=12 the Volume would be:
V=(12)^3+5(12)^2-57(12)-189
V=1,728+5(144)-684-189
V=1,728+720-684-189
V=1,575
V=W*D*H
Depth: D
Height: H
with H>D
V=1,575; W=15
Replacing in the equation above:
1,575=15*D*H
Dividing both sides by 15
1,575/15=(12*D*H)/15
105=D*H
3*5*7=D*H
D<H
If D=5→H=3*7→H=21
If D=7→H=3*5→H=15
Answer: Option <span>C. height: 21 in. depth: 5 in.
</span>
Please, see the attached file for another form to solve the problem
Width: W=(x+3) in = 15 in →x+3=15
Solving for x:
x+3-3=15-3→x=12
With x=12 the Volume would be:
V=(12)^3+5(12)^2-57(12)-189
V=1,728+5(144)-684-189
V=1,728+720-684-189
V=1,575
V=W*D*H
Depth: D
Height: H
with H>D
V=1,575; W=15
Replacing in the equation above:
1,575=15*D*H
Dividing both sides by 15
1,575/15=(12*D*H)/15
105=D*H
3*5*7=D*H
D<H
If D=5→H=3*7→H=21
If D=7→H=3*5→H=15
Answer: Option <span>C. height: 21 in. depth: 5 in.
</span>
Please, see the attached file for another form to solve the problem