Question

Difficulty: MediumInverse Proportions

A submarine leaves port with enough provisions to feed its standard crew of 120120 personnel for 6060 days. Before departure, 3030 additional mission specialists are assigned to the submarine. If the daily ration per person remains constant, how many days will the provisions last the newly expanded crew?

Answer: 48 days

Answer

48
Because the total amount of food remains constant, an increase in personnel causes a proportional decrease in the number of days the food will last. The product of personnel and days is constant: 120×60=150×x120 \times 60 = 150 \times x. Solving for xx gives 7200/150=487200 / 150 = 48 days.

Step-by-Step Solution

1
Calculate the total amount of provisions available.
120 personnel×60 days=7200 person-days120 \text{ personnel} \times 60 \text{ days} = 7200 \text{ person-days}
In an inverse proportion involving resources, the product of the number of consumers and the time the resource lasts represents the constant total resource.
2
Calculate the total number of personnel after the addition.
120+30=150 personnel120 + 30 = 150 \text{ personnel}
The problem states that 30 additional specialists were assigned, so the new crew size is the sum of the original and additional personnel.
3
Calculate the new duration the provisions will last.
7200 person-days÷150 personnel=48 days7200 \text{ person-days} \div 150 \text{ personnel} = 48 \text{ days}
Dividing the total constant resource by the new number of consumers yields the new time duration.

Key Concept

Inverse Proportions
Estimated Time:1m 0s
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