obviously a,b,c are out as non-parallel constructions.
we stick with d and e

now interesting point is that in many cases there is not any meaningful difference between selecting to+verb or for+gerund, BUT here there's one.

please note that to+verb is not only used as 'in order' before the action performed.
the construction to+verb may also serve as an adjective expressed by infinitive

ex: the person to study in HBS needs 740 GMAT <> 'to study' is adjective here means 'studying person' reversed way of placing adjective after noun, possible with '' noun+to+verb''

i went for e) right away by using this concept and by noting that in d) we have action framed in meaning by the word 'filtering'; it seems like - they are urged to equip children with breathing masks for filtering toxins - while they equip children with filtering masks not with the sole purpose of filtering - the seeming purpose is wildfires.

also 'for filtering' at the very end of sentence some how 'closes' the sentence and adds its meaning to the previous parallel constructions, therefore the use of 'to+verb' after the noun clears the issue by suggesting that 'filtering' is related to 'masks' only (functions as adjective for the masks)

vineeshp wrote:Simple question, just need help understanding the use of to and for.

Source: Grockit.

Q) Concerned about the wildfires in western Nevada, state officials are urging residents in adjacent regions to evacuate their homes, travel upwind of the wildfires, equipping children with breathing masks to filter any harmful toxins.

A) equipping children with breathing masks to filter
B) equipping children with breathing masks that filters
C) equipping children with breathing masks for filtering
D) and equip children with breathing masks for filtering
E) and equip children with breathing masks to filter.
OA is E

I need help understanding where to use "to filter" and where to use "for filtering".

Ans: E

There are 2 major errors.. the first one is parallelism among clauses and second is the use of "to/for".

Use of infinitive to give the reason is apt here.
I am not sure if we can use for <participle> for stating reason.

IMO,

'to' is used when we say something is done to with the intention to acheive something.

'for' is used to reason the action that is done.

So, in this case, 'to' fits since childrec are advised to equip breathing masks with the intention of filtering toxins.

Hope it helps.

bubbliiiiiiii wrote:'for' is used to reason the action that is done.

hey_thr67 wrote: I am not sure if we can use for <participle> for stating reason.

your inputs are challenging// agree about the use of infinitive 'to+verb' as an adjective for noun?

Thanks guys. The funny thing is, I'd have gone with "to" if I never prepared for the GMAT.

I agree, in this case "to verb" is correct since the breathing masks are used with the intent to filter toxins. This question is already answered in the link below. https://www.beatthegmat.com/preference-f ... 10211.html

I read somewhere that for is used as to reason something which is similar to the usage of 'because'.

bubbliiiiiiii wrote:I read somewhere that for is used as to reason something which is similar to the usage of 'because'.

yup to + verb is used for intention and for is used for giving reason.........