The time needed to make 138 pancakes if both Mark and Charlotte work together is 227.142 minutes.
What is a Fraction?
A fraction is a way to describe a part of a whole. such as the fraction 1/4 can be described as 0.25.
As it is given that Mark can make 9 pancakes in 15 minutes, therefore, the number of pancakes that Mark can make in one minute,
[tex]\text{Number of Pancake in one minute} = \dfrac{9}{15}[/tex]
Now, for Charlotte, it is given that he makes 42 pancakes in 45 minutes, therefore, the number of pancakes that Charlotte can make in one minute,
[tex]\text{Number of Pancake in one minute} = \dfrac{42}{45} = \dfrac{12}{15}[/tex]
Further, the total pancakes that can be made in one minute,
[tex]\text{Total Number of Pancake in one minute} = \dfrac{9}{15} +\dfrac{12}{15} = \dfrac{21}{15}[/tex]
As they both need to make 138 pancakes together, therefore, the time they need is,
[tex]\rm Time\ Needed = \dfrac{\text{Total number of pancakes}}{\text{Total number of pancakes in one minute}}[/tex]
[tex]\rm Time\ Needed = \dfrac{138}{\frac{21}{15}} = \dfrac{138\times 15}{21} = 227.142[/tex]
Hence, the time needed to make 138 pancakes if both Mark and Charlotte work together is 227.142 minutes.
Learn more about Fraction:
https://brainly.com/question/1301963
