Answer: the number would be 1.25
Explanation: Sum means addition. So, it’s ten plus a number times four. This can be expressed in an algebraic equation as:
10 + 4x = 15
you need to isolate the variable x because it is the unknown number. to determine the order to do this in, use the opposite of pemdas
subtract 10 from both sides: 4x = 5
since 4x is also 4 times x, you can use division to undo the multiplication. so 5 divided by 4 is 1.25
x = 1.25
that is your final answer! i hope this helped!! :)