Answer:
Noah has 21/10 hours left to complete the doghouse
Explanation:
To find out how much longer Noah has left to complete the doghouse, we need to subtract the time he has already spent from the total time it takes to build the doghouse.
Noah takes 4 and 1/5 hours to build the doghouse, which can also be written as a mixed fraction: 4 + 1/5 = 21/5 hours.
Noah has already been building the doghouse for 2 and 1/10 hours, which can also be written as a mixed fraction: 2 + 1/10 = 21/10 hours.
To calculate how much longer Noah has left, we subtract the time he has already spent from the total time: (21/5) - (21/10).
To subtract fractions, we need to have a common denominator. In this case, the least common multiple (LCM) of 5 and 10 is 10. We can convert both fractions to have a denominator of 10.
(21/5) - (21/10) = (42/10) - (21/10).
Now that the fractions have the same denominator, we can subtract the numerators:
(42/10) - (21/10) = 21/10.
Therefore, Noah has 21/10 hours left to complete the doghouse.