 
<translate> Tun da ɗan'uwan Greta ya karɓi wasiƙu 40, Greta ta karɓi 40 + 10 = wasiƙu 50. Tare, Greta da ɗan'uwanta sun karɓi wasiƙu 50 + 40 = 90. Mahaifiyar Greta ta karɓi adadin haruffa sau biyu fiye da adadin haruffa da Greta da ɗan'uwanta suka karɓa, wanda ya kai 90 * 2 = 180 haruffa. Gabaɗaya, waɗannan uku sun karɓi wasiƙu 90 + 180 = 270. Amsar ƙarshe: 270. <eng> 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. 