Answer:
The number of plain bagels are 18 and it is 75% of the total bagels .
The amount of salt in a plain bagel to that in a sesame bagel is 81.5% .
Step-by-step explanation:
Formula
![Percentage = \frac{Part\ value\times 100}{Total\ value}](https://tex.z-dn.net/?f=Percentage%20%3D%20%5Cfrac%7BPart%5C%20value%5Ctimes%20100%7D%7BTotal%5C%20value%7D)
As given
Jen buys sesame bagels and plain bagels. If the ratio of sesame to plain is 1:3 and Jen bought 2 dozen bagels .
As one dozens contains 12 items .
Thus
Total number of bagels bought by Jen = 2 × 12
= 24
Let us assume that the x be the scalar multiple of sesame bagels and plain bagels .
Number of sesame bagels = 1x
Number of plain bagels = 3x
Than the equation becomes
x + 3x = 24
4x = 24
![x = \frac{24}{4}](https://tex.z-dn.net/?f=x%20%3D%20%5Cfrac%7B24%7D%7B4%7D)
x = 6
Thus
Number of plain bagels = 3 × 6
= 18
Part value = 18
Total value = 24
Putting all the values in the formula
![Percentage = \frac{18\times 100}{24}](https://tex.z-dn.net/?f=Percentage%20%3D%20%5Cfrac%7B18%5Ctimes%20100%7D%7B24%7D)
![Percentage = \frac{1800}{24}](https://tex.z-dn.net/?f=Percentage%20%3D%20%5Cfrac%7B1800%7D%7B24%7D)
Percentage = 75 %
Therefore the number of plain bagels are 18 and it is 75% of the total bagels .
As given
Suppose each plain bagel has 0.53 gram of salt, and each sesame bagel has 0.65 gram.
Part value = 0.53 grams
Total value = 0.65 grams
Putting all the values in the formula
![Percentage = \frac{0.53\times 100}{0.65}](https://tex.z-dn.net/?f=Percentage%20%3D%20%5Cfrac%7B0.53%5Ctimes%20100%7D%7B0.65%7D)
![Percentage = \frac{5300}{65}](https://tex.z-dn.net/?f=Percentage%20%3D%20%5Cfrac%7B5300%7D%7B65%7D)
Percentage = 81.5 %
Therefore the amount of salt in a plain bagel to that in a sesame bagel is 81.5% .