20 greater than or equal to X less than or equal to 60
20 _
2 to 60 is 58 -48 is 10
so you have think what sort of maths skills are used like it could n+58 -48 then square or something ,but check what the differences are between the numbers.
hope it helped.
Step-by-step explanation:
50-50+15d =125-50
15d = 75
15d/15=75/15
d=5