Answer and Step-by-step explanation:
For this question, we are going to need to subtract and convert fractions into different amounts. So, the question is basically asking for you to subtract 7 1/2 ft. minus 3 4/5 ft. to find our answer if Lucas is right. With that being said, we can now solve.
To make this easier, let's make the denominator for these two numbers the same so we can subtract properly. Multiply the fractions 1/2 by 5/5, and 4/5 by 2/2 so that they both have denominators of 10. For this part, leave out the wholes numbers 7 and 3 for now.
<u>1</u> x <u>5</u> = <u>5</u> and <u>4</u> x <u>2</u> = <u>8</u>
2 x 5 = 10 and 5 x 2 = 10
Now we can bring the whole number back to have 7 5/10, and 3 8/10. But we need to make these into improper fractions to make it easier to solve. (Important:) For these steps, we need to multiply the denominator by the whole number, then add the numerator to your new answer. From there, that will be your new numerator for the improper fraction.
After doing that we have:
7 5/10 = 75/10
3 8/10 = 38/10
Now we can subtract.
<u>75</u> - <u>38</u> = <u>37</u>
10 - 10 = 10
But that's not all, to really know if Lucas was right, we need to turn this back into an improper fraction. The fraction 37/10 equals the mixed number 3 7/10, because the denominator of 10 goes into the numerator of 37 three times with a remainder of 7.
Now that we have solved, this can lead us to the conclusion that Lucas is incorrect.
I hope that this helps.