Greta received 10 more letters in the mail than her brother. Greta's mother received twice the total number of letters Greta and her brother received. Calculate the total number of letters the three received if Greta's brother received 40 letters.
Since Greta's brother received 40 letters, Greta received 40+10 = <<40+10=50>>50 letters.
Together, Greta and her brother received 50 + 40 = <<50+40=90>>90 letters.
Greta's mother received twice the total number of letters Greta and her brother received, which totals 90*2 = <<90*2=180>>180 letters.
In total, the three received 90+180 = <<90+180=270>>270 letters.
#### 270