Answer
Find out the how many calls were made by Michelle .
To proof
As given
Michelle made 26 more sales calls last month than Allen
let us assume that the number of calls made by Allen be = x
let us assume that the number of calls made by Michelle be = 26 + x
Together, they made 120 calls.
than the equation becomes
x + x + 26 = 120
2x = 120 - 26
2x = 94

x = 47
number of calls made by Allen be = 47
number of calls made by Michelle be = 26 + 47
= 73
Hence proved