sum formula

[ADIB]

please help me for the following

A B C
20 5 15
30 30
50 20 30

i want to sum b1:b3 if c1:c3 having value it mean b4 would be 25
please suggest me how i make formula for above Q
Thanks

 

[FSt1]

hi
this might work for you...
=SUMPRODUCT((B2:B4)*(C2:C4>0))

regards
FSt1