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Jamie is a cashier at a local supermarket. On average, she can check out a customer in 5 minutes.
Scott, a cashier trainee, takes an average of 8.5 minutes to check out customers.
How long would it take Jamie and Scott to check out 65 customers if they were together at different registers?
Round to two decimal places if necessary.
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The question is posed not precisely correctly.
The correctly posed question should ask to estimate the minimum possible time.
The minimum possible time is when they complete serving 65 customers at the same time (or, at close time moments).
So, let this time is about t minutes.
Then we write
+ = 65 (counting total 65 customers)
To solve the equation, multiply both sides by 5*8.5. You will get
8.5t + 5t = 65*5*8.5
13.5t = 2762.5
t = = 204.63 minutes.
CHECK. During this time, Jamie will serve = 41 customer (rounded).
Scott will serve = 24 customers (rounded).
Since 41 + 24 = 65, the solution and the answer are approximately correct.
Solved.
Another solution is possible.
Every 5*8.5 = 42.5 minutes, Jamie serves 8.5 customers; Scott serves 5 customers.
So, every 42.5 minutes they serve 5 + 8.5 = 13.5 customers.
So, they need = 4.81 times 42.5 minutes to serve 65 customers.
This number is 4.81*42.5 = 204.4 minutes to complete the job, working togeter.
Taking rounding into account, we should agree that both answers are close enough.
Solved.