Answer: 105 sandwiches can be made from all the peanut butter.
Step-by-step explanation:
Given: Total jars of peanut butter = 21
Part of peanut butter required for each sandwich = [tex]\dfrac15[/tex]
Total number of sandwiches made = ( Total jars of peanut butter ) ÷ (Part of peanut butter required for each sandwich)
[tex]=21\div\dfrac15\\\\=21\times5\\\\=105[/tex]
Hence, 105 sandwiches can be made from all the peanut butter.