Round up to intervals after cell reaches certain number

[wberg82]

I need help writing a formula that will increase a cell by a certain multiplier if and when another cell gets beyond a certain number(s). For example:

Cell G5 has a multiplier of 25. Cell B5 is where I input my number anywhere from 0-1000. Cell C5 is the output of my multiples of 25 IF the number in B5 gets past a certain point. If I type 15 in B5, then C5 is 15. However, if I type 20, then C5 rounds up to 25. If I type in 35, C5 is 35. If I type 45, C5 rounds up to 50. So on and so forth.

 

[steve the fish]

Here is a possible:

=IF(MOD(B5,25)>=20,CEILING(B5,25),B5)

 

[wberg82]

Additional information needed for more complicated formula referencing above. First, G5=B5*1.10. The result of this equation must Round Up G5 to nearest intervals of 12 depending on the result. This is the following result line:

IF the result of G5 >=9, then output is 12
IF the result of G5 >=20, then output is 24
IF the result of G5 >=30, then output is 36
IF the result of G5 >=42, then output is 48.

I should be able to put as many scenarios as I want.....

How do I add these additional parameters to the above formula?

Thanks