Answer: 160
Step-by-step explanation: The questions says that there are 144 which make up 90% of the total group.
What is the other 10%? To figure this out, we can set up a proportion which we can do in the following way:
144/t = 90/100
From here, you can cross multiply 144 x 100 = 14,400
90t = 14,400
t= 160
You can always check by plugging 160 into t to make sure the proportion is equal. I picked t as my varriable of choice which stands for team members. But you can pick an varriable (letter) to find an unknown.
In practice, is best that your child uses a calculator because in the real world, its a practical handy tool and one doesn't have time to memorize every detail by doing that long division. Once your child gets the hang of practicing setting up proportions, your child can solve a variety of problems without going back in circles.
Hope this explanation helps. Best of luck to you and your child.
