 
 <prompt> There are 25 different layers of rock in a canyon’s strata. Five of the layers are limestone. Half of the rest are sandstone. Four of the remaining are quartz. Half of the rest are shale. The rest are all different kinds of rock. How many kinds of rock make up only one layer in the canyon’s strata?``` 

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Awo ni 25 awọn ẹda to dara ni strata ti ọkan. Awo meji ni limestone. Hẹẹrẹ ti o ba miiran ni sandstone. Merin ti awọn to ba miiran ni quartz. Hẹẹrẹ ti o ba miiran ni shale. Awọn miiran gbogbo ni awọn iranlọwọ ẹda to dara. Níbẹ ni awọn ẹda kan nikan ti o wa ni strata ti ọkan?``` <response>: ```Awo ni 25 - 5 = 20 ti o ni iwe oke ti ko ni limestone.
Hawu ni awon 20 wonyi ni sandstone, bi o tile je 20 / 2 = 10 ti ko ni limestone tabi sandstone.
Merin lati awon 10 wonyi ni quartz, bi o tile je 10 - 4 = 6 ti ko ni limestone, sandstone, tabi quartz.
Hawu lati awon to wa nbe ni shale, bi o tile je 6 / 2 = 3 iran ti wa nbe ni iwe kan ni strata.

Awon iwadi yio wa ni 3.``` 