If and Whether???

tyghbn

Can someone comment on what exactly is the difference between "if" and "whether"? or if you know any of the existing links to the discussion that you can point me to, please shed the light.

thanks,

wujuao

Gmat has arbitrarily laid a regulation:if can only be used in if-clause and has the similar meaning as 'on condition that', and it cannot be used to substitute whether when expressing yes or no.

tyghbn

thanks. and makes sense...just need to make sure that this is ets' official rule...