What is the value of y if (4y + 8) - (7t - 12) = 11?

If the '7t' is supposed to be '7y', then the answer is below
(4y+8)-(7y-12)=11
distribute the negative into the second parenthesis
4y+8-7y+12=11
combine like terms
-3y+20=11
subtract the 20 from both sides
-3y=-9
divide by -3 on both sides
y=3

if it is supposed to be '7t', I'm not sure if there's enough information

Idon’t understand this but 90

She will need 5/8 bags for each square yard.