There are 480 dishes that need to be rinsed. Juan can rinse them in 80 minutes by himself. It will his friend Kevin 120 minutes
to rinse these dishes. How long will it take them if they rinse these 480 dishes together ?
1 answer:
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Answer:
Step-by-step explanation:
Given that a medical study investigated the effect of calcium and vitamin supplements on the risk of older Americans for broken bones. A total of 389 older Americans who lived at home and were in good health were studied over a three-year period. While all of the 389 people took in at least 700 milligrams of calcium and 200 units of vitamin D through their normal diet, 187 of them were given additional supplements containing 500 milligrams of calcium citrate and 70 units of vitamin D daily. Of the 187 who took additional supplements, 11 of them suffered broken bones over the three-year period. Of the 202 older Americans who did not take the additional supplement, 26 of them suffered broken bones over the study period.
Group I Group II Total
n 187 202 389
favour x 11 26 37
The fraction of older Americans who were included in the study suffered broken bones during the three-year period
=Total x/total n
=