I am using this formula to rond up times, in order to caclculate

=ROUNDUP((C28-B28)*24,0)

the only thing is sometimes it is best to rounddown,

for example, numbers under a quarter hour should go down, an numbers, or
times over a quarter hour should go up

If i only want to do the follwoing is there a formula for this

3:50 = 4:00
3:10 = 3:00
any number ending with :10 round down
any numaber ending with :50 round up?