Since if he gets the driveway done in 20 minutes he gets 1/20th of the driveway done in 1 minute (if x=20 then x/20=1 by dividing both sides by 20) and if his brother gets 1/12th of the driveway done in one minute, then if t represents the time it takes to shovel the driveway, t/20+t/12=1 driveway shoveled as 1/20+1/12=amount they can do in 1 minute, so t/20+t/12 is how much they can do in t minutes. Multiplying both sides by 20*12=240, we get 12t+20t=32t=240. Dividing both sides by 32, we get 240/32=7.5 minutes to shovel the driveway.
Answer:
The correct answer should be A not 100% sure
The x (the second one) has a one in front of it so 5x *1x=5x so 5x-4 is the answer
<u>Complete Question:</u>
Janeel has a 10 inch by 12 inch photograph. She wants to scan the photograph, then reduce the results by the same amount in each dimension to post on her Web site. Janeel wants the area of the image to be one eight of the original photograph. Write an equation to represent the area of the reduced image. Find the dimensions of the reduced image.
<u>Correct Answer:</u>
A) 
B) Dimensions are : Length = 10-x = 3 inch , Breadth = 12-x = 5 inch
<u>Step-by-step explanation:</u>
a. Write an equation to represent the area of the reduced image.
Let the reduced dimensions is by x , So the new dimensions are

According to question , Area of new image is :
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So the equation will be :
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b. Find the dimensions of the reduced image
Let's solve : 
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By Quadratic formula :
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x = 15 is rejected ! as 15 > 10 ! Side can't be negative
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Therefore, Dimensions are : Length = 10-x = 3 inch , Breadth = 12-x = 5 inch