Answer:
A: $5, $2.50; $2.50 per pound
B: 0.4 lb, 3.6 lb; 0.4 lb per dollar
Step-by-step explanation:
These tables are intended to represent proportional relationships. That means a couple of things:
- numbers in one row are some multiplier times the numbers in the other row
- ratios of numbers down the line are the same for each line.
We can use the second fact to fill these tables quickly.
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Part A
In the first table, the numbers in each column will be half the numbers in the column to its left.
- 2 pounds will have half the cost of 4 pounds, so will cost $5
- 1 pound will have half the cost of 2 pounds, so will cost $2.50
It is convenient to use the column with a weight of 1 to find the multiplier: $2.50 per pound.
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Part B
In the second table, the numbers in the second column will be 1/10 of those in the first column. The third column will be 9 times the second column.
- $1 will buy a weight 1/10 of what $10 will buy, so a weight of 0.4 pounds
- $9 will buy a weight 9 times what $1 will buy, so a weight of 3.6 pounds.
Again, the multiplier is conveniently found where the cost is $1. It is 0.4 pounds per dollar.
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Additional comment
You may notice that the first column is the same in each table. That is $2.50 per pound and 0.4 lb/dollar represent the same relationship.
