an airline has 30 airplanes in los angeles (la), 12 airplanes in st. louis (sl), and 8 airplanes in dallas (d). during an eight-hour period, 20% of the planes in la fly to sl and 10% fly to d. of the planes in sl, 25% fly to la and 50% fly to d. of the planes in d, 12.5% fly to la and 50% fly to sl. how many planes are in each city after 8 hours?

A proportion is a fraction of a total amount, and equations can be built to find the desired measures in the problem using operations such as multiplication and division, with the given ratios.

One example of application of proportions is for percentage problems, as the total amounts are multiplied by the decimal equivalent of the percentage to find the equivalent amounts.

The planes in Los Angeles after 8 hours are given as follows:

70% of 30 (that were already in Los Angeles).

25% of 12(planes that were in St. Louis).

12.5% of 8(planes that were in Dallas).

Hence the amount is:

0.7 x 30 + 0.25 x 12 + 0.125 x 8 = 25.

The planes in St. Louis after 8 hours are given as follows:

20% of 30 (planes that were in Los Angeles).

25% of 12(planes that were already in St. Louis).

50% of 8(planes that were in Dallas).

Hence the amount is:

0.2 x 30 + 0.25 x 12 + 0.5 x 8 = 13.

Initially, there were 50 planes, and 25 + 13 = 38 are in either Los Angeles or St. Louis, hence the remaining 50 - 38 = 12 are in Dallas.

More can be learned about proportions at https://brainly.com/question/24372153

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