Verified Answer :

Four times the sum of a number and 15 is at least 120

Let ‘x’ represent the number.

 "The sum of a number and 15"

This can be written mathematically as x + 15

 Given that 4 times this sum is at least 120,

This means that 4 times the sum is greater than or equal to 120

This can be written mathematically as 4(x + 15) >= 120

 Solving for x

 4(x + 15) >= 120

4x + 60 >= 120

4x >= 120 – 60

4x >= 60

x >= 60/4

x >= 15

 x is greater than or equal to 15