Tim and Todd are twins. At birth, Todd weighed 1#1/6# pounds more than Tim’s weight. If Todd weighed 7#2/3# pounds at birth, how much did Tim weigh at birth?

1 Answer
Apr 28, 2018

#6##1/2# pounds

Explanation:

The first step is to convert each mixed number into a fraction by multiplying the whole number by the denominator and adding that product to the numerator. This will give us our new numerator:

#7 * 3 + 2 = 23 | 1 * 1 + 1 = 7#
#23/3 | 7/6#

Next, we need to make sure both fractions have the same denominator. To do this, we can multiply the first fraction by #2/2# (which is equal to #1#):

#23/3 * 2/2 = 46/6#

Now that both fractions are improper and have the same denominator, we can find the difference between them by subtracting the numerator:

#46/6 - 7/6 = 39/6#

Finally, since the question gave us measurements using mixed numbers, it is a rule of thumb to convert the answer to a mixed number as well. We can do this by dividing the numerator by the denominator, leaving the remainder in the fraction, and simplifying the resulting fraction using the greatest common factor of #2#:

#39 / 6 = 6# r#3# | #6 3/6# | #6 1/2#