A teacher gives pens and pencils to elementary students at an equal rate.
Pencils Pens
18 72
29 A
35 140
B 168
Determine the missing value for the letter B.
38
42
63
70
To find the missing value for B, we can set up a proportion with the known values:
18 pencils / 72 pens = 35 pencils / 140 pens
To solve for B, we can cross multiply:
18 * 140 = 72 * 35
2520 = 2520
Since the equation is true, it means that B is the same as A, which is 168 pens.
Therefore, the missing value for B is 168 pens.
To determine the missing value for the letter B, we can set up a proportion based on the information given.
We know that the ratio of pencils to pens is equal for all cases.
Using the first case, we have 18 pencils and 72 pens, and we can set up the proportion:
18/72 = 35/140
To find the value of B, we need to determine the value of A first by using the same proportion:
18/72 = 29/A
Using cross-multiplication:
18A = 29 * 72
A = (29 * 72)/18
A = 104
Now that we have the value of A, we can set up the proportion to find the value of B:
18/72 = B/168
Using cross-multiplication:
18 * 168 = 72B
B = (18 * 168)/72
B = 42
Therefore, the missing value for the letter B is 42.