An NTSC tape would play in black and white on a pure PAL-M system. PAL-M was the Brazilian system, created to conform to the 60Hz mains but having the improved colour encoding of PAL.
Before colour TVs, Brazil used the American 60Hz System M (B&W predecessor of NTSC), so when it came time to adopt colour they couldn't choose the European PAL because it would not be compatible with current B&W TV sets, and they didn't want to adopt NTSC* because by then it was clear it was an inferior colour encoding, so they slapped a PAL colour encoding on top of a SystemM B&W signal, resulting in a 525 lines 60Hz without NTSC colour distortions (kinda best of both worlds).
* Also they didn't want to adopt NTSC because they wanted to prop the national electronics industry, so a home made standard meant local TV makers didn't have to compete with imported TV sets.
Before colour TVs, Brazil used the American 60Hz System M (B&W predecessor of NTSC), so when it came time to adopt colour they couldn't choose the European PAL because it would not be compatible with current B&W TV sets, and they didn't want to adopt NTSC* because by then it was clear it was an inferior colour encoding, so they slapped a PAL colour encoding on top of a SystemM B&W signal, resulting in a 525 lines 60Hz without NTSC colour distortions (kinda best of both worlds).
* Also they didn't want to adopt NTSC because they wanted to prop the national electronics industry, so a home made standard meant local TV makers didn't have to compete with imported TV sets.