 <translate> Since Greta's brother received 40 letters, Greta received 40 + 10 = 50 letters. Together, Greta and her brother received 50 + 40 = 90 letters. Greta's mother received twice the total number of letters Greta and her brother received, which totals 90 * 2 = 180 letters. In total, the three received 90 + 180 = 270 letters. The final answer: 270. <yor> Níwọ̀n bó ti jẹ́ pé arákùnrin Greta gba lẹ́tà ogójì, Greta náà gba lẹ́tà ogójì àti mẹ́wàá, ìyẹn sì jẹ́ àádọ́ta lẹ́tà. Àpapọ̀ iye lẹ́tà tí Greta àti àbúrò rẹ̀ gba jẹ́ àádọ́ta àti ogójì, ìyẹn sì jẹ́ àádọ́rùn-ún lẹ́tà. Ìyá Greta gba ìlọ́po méjì iye lẹ́tà tí iye tí Greta àti àbúrò rẹ̀ gbà jẹ́, èyí tó jẹ́ 90 * 2 = 180 lẹ́tà. Gbogbo lẹ́tà tí àwọn mẹ́tẹ̀ẹ̀ta gbà jẹ́ àádọ́rùn-ún [90] àti ọgọ́sàn-án [180] ó tó igba ó lé àádọ́rin [270]. Ìdáhùn tó gbẹ̀yìn ni pé: 270. 